The heart and major vessels

Victoria Johnson; Kerstin Hansson; Wilfried Maï; Joanna Dukes-McEwan; Nola Lester; Tobias Schwarz; Peter Chapman; Federica Morandi

doi:10.22233/9781910443088.7

British Small Animal Veterinary Association , 86 (2008); https://doi.org/10.22233/9781910443088.7

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The heart and major vessels

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Authors: Victoria Johnson, Kerstin Hansson, Wilfried Maï, Joanna Dukes-McEwan, Nola Lester, Tobias Schwarz, Peter Chapman and Federica Morandi
From: BSAVA Manual of Canine and Feline Thoracic Imaging
Item: Chapter 7, pp 86 - 176
DOI: 10.22233/9781910443088.7
Copyright: © 2008 British Small Animal Veterinary Association
Publication Date: January 2008

Abstract

Please note. The new 2nd edition of the BSAVA Manual of Canine and Feline Thoracic Imaging is now available here.

A thorough understanding of anatomy is an essential part of diagnostic imaging of the heart and cardiovascular system. This section covers the normal physiological and radiographic anatomy of the heart and the major vessels. An introduction to performing radiographic cardiac mensuration is also provided. The following section on interpretative principles covers the radiographic assessment of cardiac chamber enlargement, major vessel enlargement and differential diagnoses. This chapter is divided into the following sections: Radiographic anatomy, Interpretative principles; Congenital cardiovascular diseases; Myocardial diseases; Acquired valvular disease; Pericardial diseases; Cardiac neoplasia; Acquired vascular diseases.

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Figures

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7.1

Cardiac position as seen on a DV radiograph. Variation in position may be a normal variant or a congenital abnormality. Some of the reported congenital abnormalities are included; many other variants are possible. Ao = Aorta; Ap = Apex; LA = Left atrium; LV = Left ventricle; RA = Right atrium; Right ventricle; ST = Stomach. (Line diagrams adapted from Suter (1984) with permission) © 2008 British Small Animal Veterinary Association

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7.1 Cardiac position as seen on a DV radiograph. Variation in position may be a normal variant or a congenital abnormality. Some of the reported congenital abnormalities are included; many other variants are possible. Ao = Aorta; Ap = Apex; LA = Left atrium; LV = Left ventricle; RA = Right atrium; Right ventricle; ST = Stomach. (Line diagrams adapted from Suter (1984) with permission)

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7.2

Dextroposition identified as an incidental finding in a dog. The cardiac silhouette and apex are located more in the right hemithorax than in the left and there is no evidence to suggest that this is associated with a mediastinal shift. Note the normal aorta (arrowed) on the left and the gastric fundus (St) also seen on the left; there is no suggestion of a situs inversus in this dog. © 2008 British Small Animal Veterinary Association

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7.2 Dextroposition identified as an incidental finding in a dog. The cardiac silhouette and apex are located more in the right hemithorax than in the left and there is no evidence to suggest that this is associated with a mediastinal shift. Note the normal aorta (arrowed) on the left and the gastric fundus (St) also seen on the left; there is no suggestion of a situs inversus in this dog.

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7.3

Normal left-sided angiocardiogram of a 5-year-old Golden Retriever. (a) The catheter has been placed into the LV via the femoral artery and aorta ready for the contrast medium injection. (b) Positive contrast medium outlines the LV, aortic valve (arrowed), ascending aorta (Ao), brachiocephalic trunk (B) and left subclavian artery (S). (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.3 Normal left-sided angiocardiogram of a 5-year-old Golden Retriever. (a) The catheter has been placed into the LV via the femoral artery and aorta ready for the contrast medium injection. (b) Positive contrast medium outlines the LV, aortic valve (arrowed), ascending aorta (Ao), brachiocephalic trunk (B) and left subclavian artery (S). (Courtesy of J. Buchanan)

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7.4

Normal right-sided angiocardiogram of the dog in Figure 7.3 . (a) The catheter has been placed into the RV via the CdVC ready for the contrast medium injection. (b) Positive contrast medium is present within the RV and has started to enter the RVOT and main pulmonary artery (MPA). (c) The contrast medium has now reached the left and right pulmonary artery branches (arrowed) and the smaller pulmonary arterial branches in the lungs. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.4 Normal right-sided angiocardiogram of the dog in Figure 7.3 . (a) The catheter has been placed into the RV via the CdVC ready for the contrast medium injection. (b) Positive contrast medium is present within the RV and has started to enter the RVOT and main pulmonary artery (MPA). (c) The contrast medium has now reached the left and right pulmonary artery branches (arrowed) and the smaller pulmonary arterial branches in the lungs. (Courtesy of J. Buchanan)

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7.5

Location of the cardiac chambers on thoracic radiographs of a dog. (a) Lateral view. (b) Ventral view. Ao = Aortic arch; BR = Brachiocephalic trunk; CdVC = Caudal vena cava; CrVC = Cranial vena cava; IT = Internal thoracic arteries and veins; LA = Left atrium; LAu = Left auricular appendage; LPA = Left pulmonary artery; LS = Left subclavian artery; LV = Left ventricle; MPA = Main pulmonary artery; RA = Right atrium; RAu = Right auricular appendage; RPA = Right pulmonary artery; RV = Right ventricle. (Reproduced from Suter (1984) with permission) © 2008 British Small Animal Veterinary Association

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7.5 Location of the cardiac chambers on thoracic radiographs of a dog. (a) Lateral view. (b) Ventral view. Ao = Aortic arch; BR = Brachiocephalic trunk; CdVC = Caudal vena cava; CrVC = Cranial vena cava; IT = Internal thoracic arteries and veins; LA = Left atrium; LAu = Left auricular appendage; LPA = Left pulmonary artery; LS = Left subclavian artery; LV = Left ventricle; MPA = Main pulmonary artery; RA = Right atrium; RAu = Right auricular appendage; RPA = Right pulmonary artery; RV = Right ventricle. (Reproduced from Suter (1984) with permission)

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7.6

Location of the cardiac chambers on thoracic radiographs of a cat. (a) Lateral view. (b) Ventral view. Ao = Aortic arch; CdVC = Caudal vena cava; CrVC = Cranial vena cava; LA = Left atrium; LAu = Left auricular appendage; LV = Left ventricle; MPA = Main pulmonary artery; RA = Right atrium; RAu = Right auricular appendage; RV = Right ventricle. (Reproduced from Suter (1984) with permission) © 2008 British Small Animal Veterinary Association

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7.6 Location of the cardiac chambers on thoracic radiographs of a cat. (a) Lateral view. (b) Ventral view. Ao = Aortic arch; CdVC = Caudal vena cava; CrVC = Cranial vena cava; LA = Left atrium; LAu = Left auricular appendage; LV = Left ventricle; MPA = Main pulmonary artery; RA = Right atrium; RAu = Right auricular appendage; RV = Right ventricle. (Reproduced from Suter (1984) with permission)

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7.7

Clock face analogy identifying the location of the cardiac chambers. (a) Lateral view. (b) DV view. A = Aorta; LA = Left atrium; LAu = Left auricular appendage; LV = Left ventricle; MPA = Main pulmonary artery; RA = Right atrium; RAu = Right auricular appendage; RV = Right ventricle. (Reproduced from Dennis et al. (2001) with permission from the publisher) © 2008 British Small Animal Veterinary Association

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7.7 Clock face analogy identifying the location of the cardiac chambers. (a) Lateral view. (b) DV view. A = Aorta; LA = Left atrium; LAu = Left auricular appendage; LV = Left ventricle; MPA = Main pulmonary artery; RA = Right atrium; RAu = Right auricular appendage; RV = Right ventricle. (Reproduced from Dennis et al. (2001) with permission from the publisher)

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7.8

The normal cardiac silhouette in a cat is fairly constant between different breeds. (a) It is a neat ovoid shape on lateral views. (b) The cardiac silhouette is also ovoid on the DV view. Alteration in cardiac shape is useful in radiographic diagnosis of cardiac disease in the cat. © 2008 British Small Animal Veterinary Association

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7.8 The normal cardiac silhouette in a cat is fairly constant between different breeds. (a) It is a neat ovoid shape on lateral views. (b) The cardiac silhouette is also ovoid on the DV view. Alteration in cardiac shape is useful in radiographic diagnosis of cardiac disease in the cat.

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7.10

The cardiac silhouette varies markedly between different dog breeds. (a) Lateral and (b) DV radiographs of a normal Golden Retriever. This breed often appears to have right-sided cardiomegaly on the lateral view due to the large amount of sternal contact (similar to wide shallow-chested dog breeds) and the rectangular shape of the cardiac silhouette. On the DV view the cardiac size appears normal and the apex is moderately displaced into the left hemithorax. (c) Lateral radiograph of a normal Dobermann. The cardiac silhouette is extremely upright due to the deep narrow-chested nature of this breed. (d) DV radiograph of a normal Greyhound. The cardiac silhouette is very rounded in shape (compared with b) and the apex lies in the midline. © 2008 British Small Animal Veterinary Association

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7.10 The cardiac silhouette varies markedly between different dog breeds. (a) Lateral and (b) DV radiographs of a normal Golden Retriever. This breed often appears to have right-sided cardiomegaly on the lateral view due to the large amount of sternal contact (similar to wide shallow-chested dog breeds) and the rectangular shape of the cardiac silhouette. On the DV view the cardiac size appears normal and the apex is moderately displaced into the left hemithorax. (c) Lateral radiograph of a normal Dobermann. The cardiac silhouette is extremely upright due to the deep narrow-chested nature of this breed. (d) DV radiograph of a normal Greyhound. The cardiac silhouette is very rounded in shape (compared with b) and the apex lies in the midline.

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7.11

DV radiograph of an obese Domestic Shorthair cat. Note the triangular soft tissue opacity border effacing the right side of the cardiac silhouette (arrowed). This is due to a large amount of pericardial fat (even though it appears as a soft tissue opacity and should not be confused with pathology). A CT examination confirmed that no lung changes were present in this cat. © 2008 British Small Animal Veterinary Association

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7.11 DV radiograph of an obese Domestic Shorthair cat. Note the triangular soft tissue opacity border effacing the right side of the cardiac silhouette (arrowed). This is due to a large amount of pericardial fat (even though it appears as a soft tissue opacity and should not be confused with pathology). A CT examination confirmed that no lung changes were present in this cat.

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7.12

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7.12 Left lateral view of a clinically normal 12-year-old cat. In about 40% of older cats the heart has a more horizontal, cranially sloping position.

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7.14

VD views of the thorax of a Cavalier King Charles Spaniel with cardiomegaly obtained at different phases of the cardiac cycle. Note the difference in the appearance of the heart. (a) Systole: the ventricles are smaller and the atria are dilated (arrows show the RA and LAu). (b) Diastole: the entire heart is more rounded and the atrial and auricular appendage bulges are not as prominent. The changes in this dog are also exacerbated by slight differences in respiratory phase. © 2008 British Small Animal Veterinary Association

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7.14 VD views of the thorax of a Cavalier King Charles Spaniel with cardiomegaly obtained at different phases of the cardiac cycle. Note the difference in the appearance of the heart. (a) Systole: the ventricles are smaller and the atria are dilated (arrows show the RA and LAu). (b) Diastole: the entire heart is more rounded and the atrial and auricular appendage bulges are not as prominent. The changes in this dog are also exacerbated by slight differences in respiratory phase.

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7.15

Technique to perform a VHS on a lateral radiograph. L = Length of the cardiac silhouette; T4 = Fourth thoracic vertebra; W = Width of the cardiac silhouette. (Reproduced from Dennis et al. (2001) with permission from the publisher) © 2008 British Small Animal Veterinary Association

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7.15 Technique to perform a VHS on a lateral radiograph. L = Length of the cardiac silhouette; T4 = Fourth thoracic vertebra; W = Width of the cardiac silhouette. (Reproduced from Dennis et al. (2001) with permission from the publisher)

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7.17

Basic principles of tracheal and bronchial displacement on the lateral radiograph. The positions of the trachea, carina and caudal mainstem bronchi can be very useful to assess cardiac chamber enlargement. In this series of figures the changes in tracheal and bronchial position on a lateral radiograph are illustrated for various conditions. Note that there is also variation in tracheal position between different breeds of dogs. (a) Normal. The trachea and caudal mainstem bronchi have a gentle ventral divergence from the thoracic spine. Note the normal ventral bend (arrowed) in the trachea just cranial to the carina. (b) Left ventricular enlargement in isolation. The LV elevates the entire trachea when it is enlarged and there is loss of the normal ventral bend cranial to the carina. (c) Left atrial enlargement in isolation. The LA creates a triangular or wedge-shaped soft tissue opacity at the caudal border of the cardiac silhouette and pushes the left caudal mainstem bronchus (shown in dark blue) dorsally. (d) The effect of a cranial mediastinal mass is shown for comparison. A cranial mediastinal mass (shown in pink) can elevate the trachea cranial to the carina anywhere along its length. Depending on the size and location of the mass, this may be focal elevation or more commonly elevation of the entire pre-cardiac trachea. The cardiac size will be normal. (e) Right atrial enlargement or right atrial mass in isolation. It is very rare to see severe focal right atrial enlargement. An enlarged RA can focally elevate the trachea cranial to the carina. (Note that a heart base mass can also elevate the trachea in this position but usually has a different appearance on the DV/VD view; see Cardiac neoplasia.). Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and are printed with her permission. © 2008 British Small Animal Veterinary Association

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7.17 Basic principles of tracheal and bronchial displacement on the lateral radiograph. The positions of the trachea, carina and caudal mainstem bronchi can be very useful to assess cardiac chamber enlargement. In this series of figures the changes in tracheal and bronchial position on a lateral radiograph are illustrated for various conditions. Note that there is also variation in tracheal position between different breeds of dogs. (a) Normal. The trachea and caudal mainstem bronchi have a gentle ventral divergence from the thoracic spine. Note the normal ventral bend (arrowed) in the trachea just cranial to the carina. (b) Left ventricular enlargement in isolation. The LV elevates the entire trachea when it is enlarged and there is loss of the normal ventral bend cranial to the carina. (c) Left atrial enlargement in isolation. The LA creates a triangular or wedge-shaped soft tissue opacity at the caudal border of the cardiac silhouette and pushes the left caudal mainstem bronchus (shown in dark blue) dorsally. (d) The effect of a cranial mediastinal mass is shown for comparison. A cranial mediastinal mass (shown in pink) can elevate the trachea cranial to the carina anywhere along its length. Depending on the size and location of the mass, this may be focal elevation or more commonly elevation of the entire pre-cardiac trachea. The cardiac size will be normal. (e) Right atrial enlargement or right atrial mass in isolation. It is very rare to see severe focal right atrial enlargement. An enlarged RA can focally elevate the trachea cranial to the carina. (Note that a heart base mass can also elevate the trachea in this position but usually has a different appearance on the DV/VD view; see Cardiac neoplasia.). Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and are printed with her permission.

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7.18

Close-up of a lateral thoracic radiograph of a dog demonstrating the normal appearance of the caudal trachea. Note the normal ventral bend (black arrow) cranial to the carina, and the two caudal mainstem bronchi almost level with one another (white arrows point to their dorsal margins). © 2008 British Small Animal Veterinary Association

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7.18 Close-up of a lateral thoracic radiograph of a dog demonstrating the normal appearance of the caudal trachea. Note the normal ventral bend (black arrow) cranial to the carina, and the two caudal mainstem bronchi almost level with one another (white arrows point to their dorsal margins).

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7.19

(a) Close-up of a DV radiograph of a normal dog at the level of the heart. The bronchial tree is shown with black lines. The angle between the left and right caudal mainstem bronchi (shown by the arrow) should be about 60 degrees and form an upside-down V shape. This does vary somewhat with breed, but an increased angle or splayed appearance (‘cowboy legs’ sign) suggests left atrial or tracheobronchial lymph node enlargement. (b) Postmortem bronchography image showing the normal angle between the caudal mainstem bronchi. (Courtesy of B. Hopper) © 2008 British Small Animal Veterinary Association

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7.19 (a) Close-up of a DV radiograph of a normal dog at the level of the heart. The bronchial tree is shown with black lines. The angle between the left and right caudal mainstem bronchi (shown by the arrow) should be about 60 degrees and form an upside-down V shape. This does vary somewhat with breed, but an increased angle or splayed appearance (‘cowboy legs’ sign) suggests left atrial or tracheobronchial lymph node enlargement. (b) Postmortem bronchography image showing the normal angle between the caudal mainstem bronchi. (Courtesy of B. Hopper)

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7.20

(a) Lateral thoracic radiograph of a cat with a small volume of pleural fluid associated with feline leukaemia virus infection. A narrow lucent line is visible in a position compatible with the cranial aspect of the heart (arrowed). Together with the position of the trachea and the caudal aspect of the cardiac silhouette, this line has the effect of completing a normal appearing cardiac silhouette. (b) Lateral thoracic radiograph of a different cat with a larger volume of pleural fluid. In this instance, the position and size of the pericardial fat stripe, relative to the position of the trachea, suggests enlargement of the cardiac silhouette. Ultrasonography subsequently confirmed marked HCM (and ruled out a mediastinal mass). (Reproduced from Lamb (2000) with permission from Veterinary Radiology and Ultrasound) © 2008 British Small Animal Veterinary Association

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7.20 (a) Lateral thoracic radiograph of a cat with a small volume of pleural fluid associated with feline leukaemia virus infection. A narrow lucent line is visible in a position compatible with the cranial aspect of the heart (arrowed). Together with the position of the trachea and the caudal aspect of the cardiac silhouette, this line has the effect of completing a normal appearing cardiac silhouette. (b) Lateral thoracic radiograph of a different cat with a larger volume of pleural fluid. In this instance, the position and size of the pericardial fat stripe, relative to the position of the trachea, suggests enlargement of the cardiac silhouette. Ultrasonography subsequently confirmed marked HCM (and ruled out a mediastinal mass). (Reproduced from Lamb (2000) with permission from Veterinary Radiology and Ultrasound)

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7.21

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7.21 (a) Lateral and (b) DV radiographs of a dog showing the normal location and appearance of the aorta (orange arrows in (a); orange line in (b)).

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7.22

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7.22 Lateral thoracic radiograph of an aged cat. Note the focal bulge in the aorta (arrowed).

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7.23

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7.23 Close-ups of (a) lateral and (b) DV radiographs of a dog showing the normal size and location of the CdVC (green lines in (a); arrows in (b)).

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7.24

Close-up of a lateral thoracic radiograph of a dog with a severe pneumomediastinum after trauma. The azygos vein (Az) is visible as a narrow soft tissue opacity tube ventral to the spine and dorsal to the aorta (Ao), receiving tributary vessels from each intervertebral space (small white arrows). © 2008 British Small Animal Veterinary Association

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7.24 Close-up of a lateral thoracic radiograph of a dog with a severe pneumomediastinum after trauma. The azygos vein (Az) is visible as a narrow soft tissue opacity tube ventral to the spine and dorsal to the aorta (Ao), receiving tributary vessels from each intervertebral space (small white arrows).

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7.25

VD thoracic radiograph of a normal dog. The main pulmonary artery appears as a small focal bulge at the 01.00–02.00 o’clock location (arrowed). This can be a normal finding on a VD view, or when an exposure is made during systole, and should not be interpreted as disease. © 2008 British Small Animal Veterinary Association

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7.25 VD thoracic radiograph of a normal dog. The main pulmonary artery appears as a small focal bulge at the 01.00–02.00 o’clock location (arrowed). This can be a normal finding on a VD view, or when an exposure is made during systole, and should not be interpreted as disease.

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7.26

Close-up of a lateral radiograph of a dog showing the cranial lobar pulmonary vessels, the artery is shown with small white arrows and the vein with small black arrows. These vessels should be no greater than the narrowest part of the third or fourth rib (turquoise arrow) where they cross the rib (pink arrow). © 2008 British Small Animal Veterinary Association

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7.26 Close-up of a lateral radiograph of a dog showing the cranial lobar pulmonary vessels, the artery is shown with small white arrows and the vein with small black arrows. These vessels should be no greater than the narrowest part of the third or fourth rib (turquoise arrow) where they cross the rib (pink arrow).

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7.27

Close-up of a VD radiograph of a dog showing the right caudal lobar pulmonary vessels as they cross the eighth and ninth ribs. The artery is shown with small white arrows and the vein with small black arrows. The vessels are measured where they cross the ninth rib (rib measurements shown by turquoise arrows and the vessel measurements are shown by pink arrows). © 2008 British Small Animal Veterinary Association

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7.27 Close-up of a VD radiograph of a dog showing the right caudal lobar pulmonary vessels as they cross the eighth and ninth ribs. The artery is shown with small white arrows and the vein with small black arrows. The vessels are measured where they cross the ninth rib (rib measurements shown by turquoise arrows and the vessel measurements are shown by pink arrows).

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7.28

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7.28 Microcardia in a dog with Addison’s disease (hypoadrenocorticism). Note the narrow pointed appearance of the cardiac silhouette.

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7.29

Lateral radiograph of an extremely dehydrated dog. The CdVC is narrow (arrowed), the lung fields are hyperlucent, and the cardiac silhouette is small and pointed. © 2008 British Small Animal Veterinary Association

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7.29 Lateral radiograph of an extremely dehydrated dog. The CdVC is narrow (arrowed), the lung fields are hyperlucent, and the cardiac silhouette is small and pointed.

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7.30

(a) Lateral and (b) DV radiographs of a 1-year-old Kelpie cross dog and (c) DV view of an 8-month-old Golden Retriever, both with tricuspid dysplasia. The RA is enlarged on all views (arrowed). Some right ventricular enlargement is also contributing to the appearance of the cardiac silhouette. © 2008 British Small Animal Veterinary Association

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7.30 (a) Lateral and (b) DV radiographs of a 1-year-old Kelpie cross dog and (c) DV view of an 8-month-old Golden Retriever, both with tricuspid dysplasia. The RA is enlarged on all views (arrowed). Some right ventricular enlargement is also contributing to the appearance of the cardiac silhouette.

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7.31

(a) Lateral and (b) DV radiographs of a dog with a moderately enlarged RV. In (a) when a line is dropped from the carina to the apex, approximately three quarters of the cardiac silhouette lies in front of the line and one quarter lies caudal to it. In (b) the cardiac silhouette has a reverse D-shaped appearance. Note that an enlarged RA is also contributing to the shape changes. (c) DV thoracic radiograph from a different dog with severe right-sided enlargement due to heartworm disease. There is a reverse D-shaped silhouette seen in this patient. The main pulmonary artery (arrowed) is also enlarged. © 2008 British Small Animal Veterinary Association

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7.31 (a) Lateral and (b) DV radiographs of a dog with a moderately enlarged RV. In (a) when a line is dropped from the carina to the apex, approximately three quarters of the cardiac silhouette lies in front of the line and one quarter lies caudal to it. In (b) the cardiac silhouette has a reverse D-shaped appearance. Note that an enlarged RA is also contributing to the shape changes. (c) DV thoracic radiograph from a different dog with severe right-sided enlargement due to heartworm disease. There is a reverse D-shaped silhouette seen in this patient. The main pulmonary artery (arrowed) is also enlarged.

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7.32

(a) Close-up of a lateral thoracic radiograph showing moderate left atrial enlargement in a Dachshund. The left atrial outline is forming a bulging convex shape (blue line). The shape of the normal LA is shown for comparison (pink dashed line). Due to the enlargement of the LA the left mainstem bronchus is depressed (arrowed). (b) DV radiograph of a dog with marked left atrial enlargement. The increased size of the LA has separated the caudal mainstem bronchi (black lines show the outline of the bronchial tree). (c) Left atrial enlargement in the cat produces a bulge at the cranial left aspect of the cardiac silhouette on the DV/VD view. When this is accompanied by an apical shift to the right a valentine heart shape results. This is evident in this DV view of a cat with HCM. © 2008 British Small Animal Veterinary Association

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7.32 (a) Close-up of a lateral thoracic radiograph showing moderate left atrial enlargement in a Dachshund. The left atrial outline is forming a bulging convex shape (blue line). The shape of the normal LA is shown for comparison (pink dashed line). Due to the enlargement of the LA the left mainstem bronchus is depressed (arrowed). (b) DV radiograph of a dog with marked left atrial enlargement. The increased size of the LA has separated the caudal mainstem bronchi (black lines show the outline of the bronchial tree). (c) Left atrial enlargement in the cat produces a bulge at the cranial left aspect of the cardiac silhouette on the DV/VD view. When this is accompanied by an apical shift to the right a valentine heart shape results. This is evident in this DV view of a cat with HCM.

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7.33

Lateral radiograph of a dog with severe left ventricular and left atrial enlargement due to DCM. Note the tracheal position and the left atrial tent (or wedge). (Courtesy of B. Hopper) © 2008 British Small Animal Veterinary Association

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7.33 Lateral radiograph of a dog with severe left ventricular and left atrial enlargement due to DCM. Note the tracheal position and the left atrial tent (or wedge). (Courtesy of B. Hopper)

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7.34

(a) Lateral radiograph of a middle-aged crossbreed dog with generalized cardiomegaly, secondary to endocardiosis. (b) DV radiograph of a middle-aged crossbreed dog with generalized cardiomegaly, secondary to endocardiosis. © 2008 British Small Animal Veterinary Association

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7.34 (a) Lateral radiograph of a middle-aged crossbreed dog with generalized cardiomegaly, secondary to endocardiosis. (b) DV radiograph of a middle-aged crossbreed dog with generalized cardiomegaly, secondary to endocardiosis.

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7.35

(a) Lateral and (b) DV radiographs of a dog with a pericardial effusion. The cardiac silhouette is globoid on both views and careful observation reveals sharp margins. This makes pericardial effusion more likely than generalized cardiomegaly. (c) Lateral and (d) DV radiographs of a dog with pericardial effusion and right-sided heart failure. The cardiac silhouette is massively enlarged and globoid on both views. A pleural effusion is present due to the right-sided heart failure. © 2008 British Small Animal Veterinary Association

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7.35 (a) Lateral and (b) DV radiographs of a dog with a pericardial effusion. The cardiac silhouette is globoid on both views and careful observation reveals sharp margins. This makes pericardial effusion more likely than generalized cardiomegaly. (c) Lateral and (d) DV radiographs of a dog with pericardial effusion and right-sided heart failure. The cardiac silhouette is massively enlarged and globoid on both views. A pleural effusion is present due to the right-sided heart failure.

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7.36

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7.36 Lateral radiograph of a dog with subaortic stenosis. The entire aortic arch is enlarged (arrowed). This was confirmed on the DV view.

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7.37

Incidental aortic calcification identified on the lateral thoracic radiograph of a 10-year-old Weimaraner. The calcification is seen as a wavy opaque line over the cranial border of the cardiac silhouette (arrowed). © 2008 British Small Animal Veterinary Association

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7.37 Incidental aortic calcification identified on the lateral thoracic radiograph of a 10-year-old Weimaraner. The calcification is seen as a wavy opaque line over the cranial border of the cardiac silhouette (arrowed).

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7.38

(a) Enlarged main pulmonary artery seen as a bulge at the 01.00–02.00 o’clock position in a dog with pulmonic stenosis (arrowed). (b) The main pulmonary artery may mimic a nodule on the lateral radiograph when an end-on view is obtained. This may occur, on occasion, in normal dogs or, as in this case, when the main pulmonary artery is enlarged. This is a dog with heartworm disease. The end-on main pulmonary artery is shown with arrows. The radiograph is slightly rotated. © 2008 British Small Animal Veterinary Association

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7.38 (a) Enlarged main pulmonary artery seen as a bulge at the 01.00–02.00 o’clock position in a dog with pulmonic stenosis (arrowed). (b) The main pulmonary artery may mimic a nodule on the lateral radiograph when an end-on view is obtained. This may occur, on occasion, in normal dogs or, as in this case, when the main pulmonary artery is enlarged. This is a dog with heartworm disease. The end-on main pulmonary artery is shown with arrows. The radiograph is slightly rotated.

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7.39

Pulmonary arterial and venous enlargement. The main pulmonary artery and vein measurements are shown by pink arrows and the rib number is also shown. (a) Moderately enlarged cranial lobar pulmonary veins on a close-up of a lateral radiograph of a dog with heart failure. (b) Massively enlarged right caudal lobar main pulmonary artery on a DV view of a dog with heartworm disease. © 2008 British Small Animal Veterinary Association

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7.39 Pulmonary arterial and venous enlargement. The main pulmonary artery and vein measurements are shown by pink arrows and the rib number is also shown. (a) Moderately enlarged cranial lobar pulmonary veins on a close-up of a lateral radiograph of a dog with heart failure. (b) Massively enlarged right caudal lobar main pulmonary artery on a DV view of a dog with heartworm disease.

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7.41

Left-sided heart failure in the dog. (a) Lateral radiograph of the same dog as in Figure 7.33 whose marked left atrial and ventricular enlargement is now accompanied by left-sided heart failure. An increase in opacity is evident in the perihilar and caudodorsal regions, due to the presence of cardiogenic alveolar oedema. The CdVC is also wide, due to accompanying right-sided heart disease. (b) DV view. An alveolar infiltrate is present in both left and right caudal lobes. The right caudal lobe is often an early location for oedema in left heart failure. A pleural line is seen between the right middle and caudal lobes (arrowed) and represents a small amount of pleural effusion also present in this patient. © 2008 British Small Animal Veterinary Association

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7.41 Left-sided heart failure in the dog. (a) Lateral radiograph of the same dog as in Figure 7.33 whose marked left atrial and ventricular enlargement is now accompanied by left-sided heart failure. An increase in opacity is evident in the perihilar and caudodorsal regions, due to the presence of cardiogenic alveolar oedema. The CdVC is also wide, due to accompanying right-sided heart disease. (b) DV view. An alveolar infiltrate is present in both left and right caudal lobes. The right caudal lobe is often an early location for oedema in left heart failure. A pleural line is seen between the right middle and caudal lobes (arrowed) and represents a small amount of pleural effusion also present in this patient.

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7.42

Left-sided heart failure in the cat. (a) Diffuse, patchy ill defined opacities (almost appear nodular) are scattered throughout the lung fields on this lateral radiograph. In some regions there is a granular interstitial infiltrate. There is a small volume of pleural effusion, recognized by the rounding and retraction of the dorsocaudal tips of the lung lobes. (b) DV radiograph. There is an ill defined increase in opacity in the central parts of both caudal lung lobes due to cardiogenic pulmonary oedema. The small pleural effusion is also evident. (c) Lateral radiograph of another cat with left-sided heart failure. The pulmonary vessels are enlarged. In this cat a more diffuse interstitial pattern is present, more marked just cranioventral to the cardiac silhouette. The cardiac silhouette is tall. A pleural fissure line suggests the presence of a small pleural effusion. An incidental old sternal injury is present between the third and fourth sternebrae. © 2008 British Small Animal Veterinary Association

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7.42 Left-sided heart failure in the cat. (a) Diffuse, patchy ill defined opacities (almost appear nodular) are scattered throughout the lung fields on this lateral radiograph. In some regions there is a granular interstitial infiltrate. There is a small volume of pleural effusion, recognized by the rounding and retraction of the dorsocaudal tips of the lung lobes. (b) DV radiograph. There is an ill defined increase in opacity in the central parts of both caudal lung lobes due to cardiogenic pulmonary oedema. The small pleural effusion is also evident. (c) Lateral radiograph of another cat with left-sided heart failure. The pulmonary vessels are enlarged. In this cat a more diffuse interstitial pattern is present, more marked just cranioventral to the cardiac silhouette. The cardiac silhouette is tall. A pleural fissure line suggests the presence of a small pleural effusion. An incidental old sternal injury is present between the third and fourth sternebrae.

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7.43

(a) Lateral and (b) DV radiographs of a dog with right-sided heart failure. A large volume of pleural effusion is present, obscuring the cardiac silhouette. The dog also has ascites and an enlarged liver (not seen on these radiographs). An enlarged right pulmonary caudal lobar vein (arrowed) suggests that pulmonary venous congestion may also be present due to left-sided heart disease. It is not possible to identify the cause of the effusion from these radiographs and further work-up would be required to confirm right-sided heart failure. © 2008 British Small Animal Veterinary Association

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7.43 (a) Lateral and (b) DV radiographs of a dog with right-sided heart failure. A large volume of pleural effusion is present, obscuring the cardiac silhouette. The dog also has ascites and an enlarged liver (not seen on these radiographs). An enlarged right pulmonary caudal lobar vein (arrowed) suggests that pulmonary venous congestion may also be present due to left-sided heart disease. It is not possible to identify the cause of the effusion from these radiographs and further work-up would be required to confirm right-sided heart failure.

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7.45

Lateral view of the thorax of a 3-month-old male puppy with PDA. There is mainly left-sided cardiomegaly with left atrial tent formation. Both the arteries and veins to the cranial lung lobes were enlarged (difficult to see on this image), which is a sign of a left-to-right shunt. © 2008 British Small Animal Veterinary Association

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7.45 Lateral view of the thorax of a 3-month-old male puppy with PDA. There is mainly left-sided cardiomegaly with left atrial tent formation. Both the arteries and veins to the cranial lung lobes were enlarged (difficult to see on this image), which is a sign of a left-to-right shunt.

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7.46

(a) DV view of the thorax of a dog with PDA. The cardiac silhouette is very long in a craniocaudal direction and there is bulging of the aortic arch, main pulmonary artery (MPA) and left auricular appendage (LAu). (b) Close-up of (a) showing the left caudal thorax. The artery and vein to the left caudal lung lobe (arrowed) have a diameter wider than the width of the ninth rib where they cross it. This is consistent with left-to-right shunting as seen with PDA. © 2008 British Small Animal Veterinary Association

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7.46 (a) DV view of the thorax of a dog with PDA. The cardiac silhouette is very long in a craniocaudal direction and there is bulging of the aortic arch, main pulmonary artery (MPA) and left auricular appendage (LAu). (b) Close-up of (a) showing the left caudal thorax. The artery and vein to the left caudal lung lobe (arrowed) have a diameter wider than the width of the ninth rib where they cross it. This is consistent with left-to-right shunting as seen with PDA.

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7.47

Angiocardiogram demonstrating a left-to-right shunt through a PDA in a dog. The contrast medium was injected in the aorta and the opacified ductus is seen (PDA). The contrast medium is opacifying the main pulmonary artery (MPA) at the same time as the aorta (Ao). BCT = Brachiocephalic trunk; LSCA = Left subclavian artery. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.47 Angiocardiogram demonstrating a left-to-right shunt through a PDA in a dog. The contrast medium was injected in the aorta and the opacified ductus is seen (PDA). The contrast medium is opacifying the main pulmonary artery (MPA) at the same time as the aorta (Ao). BCT = Brachiocephalic trunk; LSCA = Left subclavian artery. (Courtesy of J. Buchanan)

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7.48

LPS echocardiogram in a dog with a PDA, optimized for visualization of the ductus. The 2D image on the left demonstrates the appearance of the ductus itself at its connection with the main pulmonary artery (MPA). The aorta (Ao) and right ventricular outflow tract (RVOT) are also shown. The colour Doppler image on the right was acquired simultaneously and turbulent flow is evident within the ductus. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.48 LPS echocardiogram in a dog with a PDA, optimized for visualization of the ductus. The 2D image on the left demonstrates the appearance of the ductus itself at its connection with the main pulmonary artery (MPA). The aorta (Ao) and right ventricular outflow tract (RVOT) are also shown. The colour Doppler image on the right was acquired simultaneously and turbulent flow is evident within the ductus. (© J. Dukes-McEwan)

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7.49

RPS short-axis echocardiogram of the heart base in a dog with a PDA. Colour Doppler shows turbulent flow in the main pulmonary artery (MPA), corresponding to the shunting of blood from the aorta (Ao). LA = Left atrium. (Courtesy of M. Sleeper) © 2008 British Small Animal Veterinary Association

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7.49 RPS short-axis echocardiogram of the heart base in a dog with a PDA. Colour Doppler shows turbulent flow in the main pulmonary artery (MPA), corresponding to the shunting of blood from the aorta (Ao). LA = Left atrium. (Courtesy of M. Sleeper)

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7.50

CW Doppler trace acquired via a LPS window in a dog with a PDA. The cursor is aligned with the ductus and continuous flow is evident throughout systole and diastole. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.50 CW Doppler trace acquired via a LPS window in a dog with a PDA. The cursor is aligned with the ductus and continuous flow is evident throughout systole and diastole. (© J. Dukes-McEwan)

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7.51

Left lateral images obtained at four frames per second during a first pass radionuclide angiogram in an 8-month-old Poodle with a left-to-right PDA. Notice the lack of clearance of the lungs in the levophase consistent with pulmonary recirculation; the aorta is never visible. The LA and LV are enlarged, consistent with volume overload. CrVC = Cranial vena cava. © 2008 British Small Animal Veterinary Association

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7.51 Left lateral images obtained at four frames per second during a first pass radionuclide angiogram in an 8-month-old Poodle with a left-to-right PDA. Notice the lack of clearance of the lungs in the levophase consistent with pulmonary recirculation; the aorta is never visible. The LA and LV are enlarged, consistent with volume overload. CrVC = Cranial vena cava.

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7.52

Angiocardiogram demonstrating a right-to-left shunt through a PDA in a case where significant pulmonary hypertension was present. The contrast medium was injected in the RV, and the aorta (Ao) is opacified at the same time as the main pulmonary artery (MPA). The region of the PDA is indicated by the arrow. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.52 Angiocardiogram demonstrating a right-to-left shunt through a PDA in a case where significant pulmonary hypertension was present. The contrast medium was injected in the RV, and the aorta (Ao) is opacified at the same time as the main pulmonary artery (MPA). The region of the PDA is indicated by the arrow. (Courtesy of J. Buchanan)

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7.53

Left lateral images obtained at four frames per second during first pass radionuclide angiogram in a 6-month-old Collie with a right-to-left shunt. Notice the simultaneous visualization of the main pulmonary artery and aorta (*). A final diagnosis was not reached in this case as the owner elected euthanasia without necropsy. CrVC = Cranial vena cava. © 2008 British Small Animal Veterinary Association

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7.53 Left lateral images obtained at four frames per second during first pass radionuclide angiogram in a 6-month-old Collie with a right-to-left shunt. Notice the simultaneous visualization of the main pulmonary artery and aorta (*). A final diagnosis was not reached in this case as the owner elected euthanasia without necropsy. CrVC = Cranial vena cava.

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7.54

Whole body composite left lateral static image of a 1-year-old Toy Poodle with polycythaemia, obtained 5 minutes after intravenous injection of 99mTc-MAA. The patient’s head is to the left of the image. Note the extrapulmonary distribution of the radiopharmaceutical, with marked uptake at the level of the kidneys (arrowed). Notice also the sharp cut-off at the level of the front limbs, with no radiopharmaceutical distribution to the neck, head and brain. This is consistent with a reverse PDA, in which the radioactive particles are shunted from the pulmonary to the systemic circulation caudal to the brachiocephalic trunk and left subclavian arteries. © 2008 British Small Animal Veterinary Association

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7.54 Whole body composite left lateral static image of a 1-year-old Toy Poodle with polycythaemia, obtained 5 minutes after intravenous injection of 99mTc-MAA. The patient’s head is to the left of the image. Note the extrapulmonary distribution of the radiopharmaceutical, with marked uptake at the level of the kidneys (arrowed). Notice also the sharp cut-off at the level of the front limbs, with no radiopharmaceutical distribution to the neck, head and brain. This is consistent with a reverse PDA, in which the radioactive particles are shunted from the pulmonary to the systemic circulation caudal to the brachiocephalic trunk and left subclavian arteries.

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7.55

Normal coronary artery distribution in dogs and humans, and common patterns of single right coronary artery in the latter. In the type R1 pattern, the right coronary artery (RCA) continues as a single vessel and crosses the caudal crux of the atrioventricular sulcus (open arrow), then continues as the left circumflex (LCx) and left caudal descending (LCD) arteries. In type 2 patterns, the single vessel branches shortly after leaving the aorta. Sub-classifications are made depending on whether the crossing vessel (solid arrow) passes cranial to the pulmonary trunk (PT) (R2A), between the aorta and pulmonary trunk (R2B) or caudal to the aorta (R2C). (Reproduced from Buchanan (1990) with permission from the Journal of the American Veterinary Medical Association) © 2008 British Small Animal Veterinary Association

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7.55 Normal coronary artery distribution in dogs and humans, and common patterns of single right coronary artery in the latter. In the type R1 pattern, the right coronary artery (RCA) continues as a single vessel and crosses the caudal crux of the atrioventricular sulcus (open arrow), then continues as the left circumflex (LCx) and left caudal descending (LCD) arteries. In type 2 patterns, the single vessel branches shortly after leaving the aorta. Sub-classifications are made depending on whether the crossing vessel (solid arrow) passes cranial to the pulmonary trunk (PT) (R2A), between the aorta and pulmonary trunk (R2B) or caudal to the aorta (R2C). (Reproduced from Buchanan (1990) with permission from the Journal of the American Veterinary Medical Association)

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7.56

West Highland White Terrier with pulmonic stenosis. (a) Lateral view of the thorax. There is rounding of the cranioventral border of the heart and increased sternal contact, consistent with right-sided cardiomegaly. The dilated post-stenotic main pulmonary artery segment is seen protruding dorsally from the heart base (arrowed) and is superimposed over the ventral aspect of the caudal trachea. This feature has been termed the ‘hat sign’. (b) VD view of the thorax. The cardiac silhouette has a reversed D shape, consistent with right-sided cardiomegaly. There is also a soft tissue opacity bulging out of the cardiac silhouette at the left fourth intercostal space, between 01.00 and 02.00 o’clock, consistent with dilatation of the main pulmonary artery. A catheter is present in preparation for an angiogram. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.56 West Highland White Terrier with pulmonic stenosis. (a) Lateral view of the thorax. There is rounding of the cranioventral border of the heart and increased sternal contact, consistent with right-sided cardiomegaly. The dilated post-stenotic main pulmonary artery segment is seen protruding dorsally from the heart base (arrowed) and is superimposed over the ventral aspect of the caudal trachea. This feature has been termed the ‘hat sign’. (b) VD view of the thorax. The cardiac silhouette has a reversed D shape, consistent with right-sided cardiomegaly. There is also a soft tissue opacity bulging out of the cardiac silhouette at the left fourth intercostal space, between 01.00 and 02.00 o’clock, consistent with dilatation of the main pulmonary artery. A catheter is present in preparation for an angiogram. (Courtesy of J. Buchanan)

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7.57

Angiocardiogram after injection of contrast medium in the RV. Same dog as Figure 7.56 . (a) On the lateral view the main pulmonary artery is opacified and there is a clear narrowing at the level of the infundibulum as well as post-stenotic dilatation of the main pulmonary artery. (b) On the VD view the main pulmonary artery is opacified and there is a clear dilatation. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.57 Angiocardiogram after injection of contrast medium in the RV. Same dog as Figure 7.56 . (a) On the lateral view the main pulmonary artery is opacified and there is a clear narrowing at the level of the infundibulum as well as post-stenotic dilatation of the main pulmonary artery. (b) On the VD view the main pulmonary artery is opacified and there is a clear dilatation. (Courtesy of J. Buchanan)

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7.58

Angiocardiogram in a Bulldog with a pulmonic stenosis. The contrast medium injection was made in the LVOT in order to opacify the aorta and the coronary arteries. A single coronary artery (arrowed) is seen, which then branches into a right and left coronary artery. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.58 Angiocardiogram in a Bulldog with a pulmonic stenosis. The contrast medium injection was made in the LVOT in order to opacify the aorta and the coronary arteries. A single coronary artery (arrowed) is seen, which then branches into a right and left coronary artery. (Courtesy of J. Buchanan)

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7.59

RPS short-axis echocardiogram at the level of the ventricles in a dog with pulmonic stenosis. There is a clear concentric hypertrophy of the right ventricle (RV) and flattening of the IVS, secondary to the pressure overload on the RV. LV = Left ventricle. © 2008 British Small Animal Veterinary Association

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7.59 RPS short-axis echocardiogram at the level of the ventricles in a dog with pulmonic stenosis. There is a clear concentric hypertrophy of the right ventricle (RV) and flattening of the IVS, secondary to the pressure overload on the RV. LV = Left ventricle.

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7.60

(a) RPS long-axis four-chamber view from a Lhasa Apso with pulmonic stenosis. Note the right ventricular hypertrophy and the right atrial enlargement. (b) RPS short-axis view at the level of the papillary muscles. The right ventricular free wall is markedly thickened and the IVS is flattened. (c) An M mode echocardiogram acquired from the level shown in (b). Paradoxical motion of the IVS is present. IVS = Interventricular septum; LA = Left atrium; LV = Left ventricle; LVFW = Left ventricular free wall; RA = Right atrium; RV = Right ventricle; RVFW = Right ventricular free wall. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.60 (a) RPS long-axis four-chamber view from a Lhasa Apso with pulmonic stenosis. Note the right ventricular hypertrophy and the right atrial enlargement. (b) RPS short-axis view at the level of the papillary muscles. The right ventricular free wall is markedly thickened and the IVS is flattened. (c) An M mode echocardiogram acquired from the level shown in (b). Paradoxical motion of the IVS is present. IVS = Interventricular septum; LA = Left atrium; LV = Left ventricle; LVFW = Left ventricular free wall; RA = Right atrium; RV = Right ventricle; RVFW = Right ventricular free wall. (© J. Dukes-McEwan)

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7.61

(a) LPS view optimized for the right ventricular outflow tract (RVOT) in a crossbred Labrador Retriever with pulmonic stenosis. Markedly thickened pulmonic valve leaflets are seen and there is a prominent post-stenotic dilatation of the main pulmonary artery (MPA). The aorta (Ao) is also seen in short axis. (b) LPS short-axis view. The pulmonic valve is seen in short axis during diastole. The valve leaflets (arrowed) are thickened and echogenic. The aorta is also seen on this image. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.61 (a) LPS view optimized for the right ventricular outflow tract (RVOT) in a crossbred Labrador Retriever with pulmonic stenosis. Markedly thickened pulmonic valve leaflets are seen and there is a prominent post-stenotic dilatation of the main pulmonary artery (MPA). The aorta (Ao) is also seen in short axis. (b) LPS short-axis view. The pulmonic valve is seen in short axis during diastole. The valve leaflets (arrowed) are thickened and echogenic. The aorta is also seen on this image. (© J. Dukes-McEwan)

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7.62

Spectral Doppler study of the main pulmonary artery in a dog with pulmonic stenosis. There is an increased velocity of the ejection flow, which is higher than 4 m/s. There is also a diastolic regurgitation from the main pulmonary artery to the RV due to some pulmonic insufficiency. (Courtesy of M. Oyama) © 2008 British Small Animal Veterinary Association

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7.62 Spectral Doppler study of the main pulmonary artery in a dog with pulmonic stenosis. There is an increased velocity of the ejection flow, which is higher than 4 m/s. There is also a diastolic regurgitation from the main pulmonary artery to the RV due to some pulmonic insufficiency. (Courtesy of M. Oyama)

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7.63

Colour Doppler study of the main pulmonary artery in a dog with pulmonic stenosis. There is a turbulent flow in the main pulmonary artery during systole as indicated by a mosaic-like colour display of the flow. Ao = Aorta; MPA = Main pulmonary artery. (Courtesy of M. Oyama) © 2008 British Small Animal Veterinary Association

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7.63 Colour Doppler study of the main pulmonary artery in a dog with pulmonic stenosis. There is a turbulent flow in the main pulmonary artery during systole as indicated by a mosaic-like colour display of the flow. Ao = Aorta; MPA = Main pulmonary artery. (Courtesy of M. Oyama)

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7.64

(a) Lateral view of the thorax in a dog with aortic stenosis. There is a marked rounding and bulging of the cardiac silhouette cranially in the region of the aortic arch. (b) VD view of the thorax. There is a marked bulge of the aortic arch visible between 11.00 and 01.00 o’clock (arrowed). © 2008 British Small Animal Veterinary Association

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7.64 (a) Lateral view of the thorax in a dog with aortic stenosis. There is a marked rounding and bulging of the cardiac silhouette cranially in the region of the aortic arch. (b) VD view of the thorax. There is a marked bulge of the aortic arch visible between 11.00 and 01.00 o’clock (arrowed).

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7.65

Angiocardiogram in a dog with subaortic stenosis. The contrast medium was injected in the RA and this is the levophase of the study, 7 seconds after injection of the contrast medium. There is clear narrowing of the subaortic region (arrowed) and mild post-stenotic dilatation of the aorta. Some degree of concentric hypertrophy of the LV can also be appreciated on this view. Ao = Aorta; LA = Left atrium; LV = Left ventricle. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.65 Angiocardiogram in a dog with subaortic stenosis. The contrast medium was injected in the RA and this is the levophase of the study, 7 seconds after injection of the contrast medium. There is clear narrowing of the subaortic region (arrowed) and mild post-stenotic dilatation of the aorta. Some degree of concentric hypertrophy of the LV can also be appreciated on this view. Ao = Aorta; LA = Left atrium; LV = Left ventricle. (Courtesy of J. Buchanan)

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7.66

(a) RPS short-axis echocardiogram at the level of the papillary muscles in a dog with subaortic stenosis. There is concentric hypertrophy of the left ventricle. The papillary muscles are more prominent than normal. The left ventricular cavity is reduced in this image acquired in diastole. (b) RPS five-chamber view of a Maine Coon cat with valvular and supravalvular aortic stenosis. Two focal regions of narrowing are identified in the LVOT and there is dilatation of the post-stenotic aorta (Ao). LV = Left ventricle. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.66 (a) RPS short-axis echocardiogram at the level of the papillary muscles in a dog with subaortic stenosis. There is concentric hypertrophy of the left ventricle. The papillary muscles are more prominent than normal. The left ventricular cavity is reduced in this image acquired in diastole. (b) RPS five-chamber view of a Maine Coon cat with valvular and supravalvular aortic stenosis. Two focal regions of narrowing are identified in the LVOT and there is dilatation of the post-stenotic aorta (Ao). LV = Left ventricle. (© J. Dukes-McEwan)

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7.67

(a) RPS five-chamber view from a German Shepherd Dog with subvalvular aortic stenosis. Note the prominent ridge in close proximity to and just below the aortic valve. (b) RPS five-chamber view, showing a colour Doppler map of the aortic outflow during systole. Note the turbulent flow within the aorta due to the stenosis. (c) CW Doppler trace from the aorta obtained from a subcostal position. A maximal aortic velocity of 3.99 m/s was recorded. The maximal aortic velocity in most dogs is 1.7 m/s. Ao = Aorta; LV = Left ventricle; RV = Right ventricle. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.67 (a) RPS five-chamber view from a German Shepherd Dog with subvalvular aortic stenosis. Note the prominent ridge in close proximity to and just below the aortic valve. (b) RPS five-chamber view, showing a colour Doppler map of the aortic outflow during systole. Note the turbulent flow within the aorta due to the stenosis. (c) CW Doppler trace from the aorta obtained from a subcostal position. A maximal aortic velocity of 3.99 m/s was recorded. The maximal aortic velocity in most dogs is 1.7 m/s. Ao = Aorta; LV = Left ventricle; RV = Right ventricle. (© J. Dukes-McEwan)

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7.68

Thorax of a cat with a VSD. (a) Lateral view. There is generalized cardiomegaly and a marked increase in the vascular pattern of the lungs, which is consistent with left-to-right shunting. The cat had a pectus excavatum, making accurate positioning difficult. (b) VD view. There is moderate generalized cardiomegaly and enlargement of the caudal pulmonary lobar arteries and veins. © 2008 British Small Animal Veterinary Association

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7.68 Thorax of a cat with a VSD. (a) Lateral view. There is generalized cardiomegaly and a marked increase in the vascular pattern of the lungs, which is consistent with left-to-right shunting. The cat had a pectus excavatum, making accurate positioning difficult. (b) VD view. There is moderate generalized cardiomegaly and enlargement of the caudal pulmonary lobar arteries and veins.

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7.69

Angiocardiogram in a dog with a VSD. The contrast medium was injected in the LV and shunting can be seen from the LV to the RV through a membranous VSD (arrowed). There is also eccentric hypertrophy of the LV. The LA also appears dilated. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.69 Angiocardiogram in a dog with a VSD. The contrast medium was injected in the LV and shunting can be seen from the LV to the RV through a membranous VSD (arrowed). There is also eccentric hypertrophy of the LV. The LA also appears dilated. (Courtesy of J. Buchanan)

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7.70

(a) RPS long-axis echocardiogram in a dog with a VSD. The defect is clearly visible (arrowed). There is mild left ventricular and atrial dilatation. (Courtesy of M. Oyama) (b) Colour Doppler study in a dog with a VSD. On this RPS long-axis echocardiogram, shunting is clearly seen as a turbulent flow through the defect from the LV to the RV (arrowed). There is left ventricular and atrial dilatation as well as right ventricular dilatation. Ao = Aorta; LA = Left atrium; LV = Left ventricle; RV = Right ventricle. (Courtesy of M. Sleeper) © 2008 British Small Animal Veterinary Association

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7.70 (a) RPS long-axis echocardiogram in a dog with a VSD. The defect is clearly visible (arrowed). There is mild left ventricular and atrial dilatation. (Courtesy of M. Oyama) (b) Colour Doppler study in a dog with a VSD. On this RPS long-axis echocardiogram, shunting is clearly seen as a turbulent flow through the defect from the LV to the RV (arrowed). There is left ventricular and atrial dilatation as well as right ventricular dilatation. Ao = Aorta; LA = Left atrium; LV = Left ventricle; RV = Right ventricle. (Courtesy of M. Sleeper)

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7.71

(a) RPS long-axis five-chamber view from a Cavalier King Charles Spaniel with a VSD and Eisenmenger’s complex. The blood flows from right-to-left across the defect in this case (seen as blue on the colour Doppler map). (b) RPS short-axis view at the level of the ventricles. The small right-to-left shunting VSD is identified by colour Doppler as flow from the RV to the LV. This can be a subtle finding and is easily missed unless a careful and thorough examination is undertaken. Ao = Aorta; LV = Left ventricle; RV = Right ventricle. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.71 (a) RPS long-axis five-chamber view from a Cavalier King Charles Spaniel with a VSD and Eisenmenger’s complex. The blood flows from right-to-left across the defect in this case (seen as blue on the colour Doppler map). (b) RPS short-axis view at the level of the ventricles. The small right-to-left shunting VSD is identified by colour Doppler as flow from the RV to the LV. This can be a subtle finding and is easily missed unless a careful and thorough examination is undertaken. Ao = Aorta; LV = Left ventricle; RV = Right ventricle. (© J. Dukes-McEwan)

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7.72

Left lateral images obtained at four frames per second during first pass radionuclide angiogram in a 1-year-old cat with a VSD. Notice the lack of clearance of the lungs in the levophase and the lack of distinction of the margins of the aorta, consistent with pulmonary recirculation in a left-to-right shunt. In this case, reappearance of the RV in the levophase (arrowed) indicates a VSD. © 2008 British Small Animal Veterinary Association

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7.72 Left lateral images obtained at four frames per second during first pass radionuclide angiogram in a 1-year-old cat with a VSD. Notice the lack of clearance of the lungs in the levophase and the lack of distinction of the margins of the aorta, consistent with pulmonary recirculation in a left-to-right shunt. In this case, reappearance of the RV in the levophase (arrowed) indicates a VSD.

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7.73

DV view of the thorax in a dog with an ASD. There is mild rounding of the cardiac silhouette in the region of the RA, between 09.00 and 11.00 o’clock. © 2008 British Small Animal Veterinary Association

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7.73 DV view of the thorax in a dog with an ASD. There is mild rounding of the cardiac silhouette in the region of the RA, between 09.00 and 11.00 o’clock.

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7.74

RPS long-axis echocardiogram in a dog with an ASD. The defect is clearly seen as an interruption of the echogenic line of the interatrial septum (arrowed). LA = Left atrium; LV = Left ventricle; RA = Right atrium. © 2008 British Small Animal Veterinary Association

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7.74 RPS long-axis echocardiogram in a dog with an ASD. The defect is clearly seen as an interruption of the echogenic line of the interatrial septum (arrowed). LA = Left atrium; LV = Left ventricle; RA = Right atrium.

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7.75

RPS long-axis four-chamber view of a Boxer with an ostium secundum type ASD. Flow across the defect is identified. ASD = Atrial septal defect; LA = Left atrium; RA = Right atrium. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.75 RPS long-axis four-chamber view of a Boxer with an ostium secundum type ASD. Flow across the defect is identified. ASD = Atrial septal defect; LA = Left atrium; RA = Right atrium. (© J. Dukes-McEwan)

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7.76

RPS four-chamber echocardiogram of a cat with an endocardial cushion defect. A large VSD and ASD are present. LA = Left atrium; LV = Left ventricle; RA = Right atrium; RV = Right ventricle. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.76 RPS four-chamber echocardiogram of a cat with an endocardial cushion defect. A large VSD and ASD are present. LA = Left atrium; LV = Left ventricle; RA = Right atrium; RV = Right ventricle. (© J. Dukes-McEwan)

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7.77

Lateral view of the thorax in a dog with mitral valve dysplasia. There is a marked dilatation of the LA, creating a prominent bulge between 12.00 and 03.00 o’clock. © 2008 British Small Animal Veterinary Association

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7.77 Lateral view of the thorax in a dog with mitral valve dysplasia. There is a marked dilatation of the LA, creating a prominent bulge between 12.00 and 03.00 o’clock.

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7.78

(a) Left apical echocardiogram of a dog with mitral valve dysplasia, presenting with both mitral stenosis and regurgitation as a functional consequence of the valvular malformation. There is marked dilatation of the LA. Note the lack of opening of the mitral valve leaflets, leading to a mitral stenosis (arrowed) in this diastolic image. (b) Left apical echocardiogram colour Doppler study in systole. There is a mitral regurgitation with a high-velocity, turbulent flow. LA = Left atrium; LV = Left ventricle. © 2008 British Small Animal Veterinary Association

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7.78 (a) Left apical echocardiogram of a dog with mitral valve dysplasia, presenting with both mitral stenosis and regurgitation as a functional consequence of the valvular malformation. There is marked dilatation of the LA. Note the lack of opening of the mitral valve leaflets, leading to a mitral stenosis (arrowed) in this diastolic image. (b) Left apical echocardiogram colour Doppler study in systole. There is a mitral regurgitation with a high-velocity, turbulent flow. LA = Left atrium; LV = Left ventricle.

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7.79

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7.79 Lateral view of the thorax in a puppy with tricuspid valve dysplasia. Right-sided cardiomegaly is evident.

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7.80

RPS long-axis echocardiogram in a dog with tricuspid valve dysplasia. Marked dilatation of the right cardiac chambers is evident. The RV is almost larger than the LV and the IVS is flat and pushed to the left side of the heart. Colour Doppler shows a turbulent high-velocity tricuspid regurgitation. LA = Left atrium; LV = Left ventricle; RV = Right ventricle. (Courtesy of M. Oyama) © 2008 British Small Animal Veterinary Association

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7.80 RPS long-axis echocardiogram in a dog with tricuspid valve dysplasia. Marked dilatation of the right cardiac chambers is evident. The RV is almost larger than the LV and the IVS is flat and pushed to the left side of the heart. Colour Doppler shows a turbulent high-velocity tricuspid regurgitation. LA = Left atrium; LV = Left ventricle; RV = Right ventricle. (Courtesy of M. Oyama)

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7.81

Spectral Doppler study of the tricuspid valve in a dog with tricuspid dysplasia. There is a systolic high-velocity tricuspid regurgitation reaching 3 m/s (arrowed). A = Normal diastolic inflow A wave; E = Normal diastolic inflow E wave. (Courtesy of M. Oyama) © 2008 British Small Animal Veterinary Association

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7.81 Spectral Doppler study of the tricuspid valve in a dog with tricuspid dysplasia. There is a systolic high-velocity tricuspid regurgitation reaching 3 m/s (arrowed). A = Normal diastolic inflow A wave; E = Normal diastolic inflow E wave. (Courtesy of M. Oyama)

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7.82

Lateral view of the thorax in a dog with tetralogy of Fallot. There is mild right-sided cardiomegaly. Note also the loss of the cranial indentation (or waist) of the cardiac silhouette, which is probably secondary to the overriding of the aorta. The changes are subtle. Diffuse hyperlucency of the lung fields is identified due to hypovascularization. © 2008 British Small Animal Veterinary Association

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7.82 Lateral view of the thorax in a dog with tetralogy of Fallot. There is mild right-sided cardiomegaly. Note also the loss of the cranial indentation (or waist) of the cardiac silhouette, which is probably secondary to the overriding of the aorta. The changes are subtle. Diffuse hyperlucency of the lung fields is identified due to hypovascularization.

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7.83

Angiocardiogram in a dog with tetralogy of Fallot. The contrast medium was injected in the RV. There is narrowing of the main pulmonary artery at the infundibular level (arrowed) and there is simultaneous opacification of the main pulmonary artery and the aorta, which means that there is a right-to-left shunt. Ao = Aorta; LV = Left ventricle; MPA = Main pulmonary artery; RV = Right ventricle. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.83 Angiocardiogram in a dog with tetralogy of Fallot. The contrast medium was injected in the RV. There is narrowing of the main pulmonary artery at the infundibular level (arrowed) and there is simultaneous opacification of the main pulmonary artery and the aorta, which means that there is a right-to-left shunt. Ao = Aorta; LV = Left ventricle; MPA = Main pulmonary artery; RV = Right ventricle. (Courtesy of J. Buchanan)

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7.84

RPS long-axis echocardiogram in a dog with tetralogy of Fallot. There is overriding of the aorta (double-headed arrow) over the IVS. A VSD is created by this abnormal position of the aorta. Ao = Aorta; LA = Left atrium; LV = Left ventricle; RV = Right ventricle. © 2008 British Small Animal Veterinary Association

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7.84 RPS long-axis echocardiogram in a dog with tetralogy of Fallot. There is overriding of the aorta (double-headed arrow) over the IVS. A VSD is created by this abnormal position of the aorta. Ao = Aorta; LA = Left atrium; LV = Left ventricle; RV = Right ventricle.

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7.85

(a) RPS long-axis five-chamber echocardiogram of a Border Collie with tetralogy of Fallot. The aorta is overriding or dextraposed and a high VSD is present. (b) RPS short-axis view obtained at the level of the heart base and optimized for the RVOT. The pulmonic valve is stenotic and the valves are thickened and echogenic. The main pulmonary artery is hypoplastic. (c) RPS long-axis five-chamber view with colour Doppler. Blood is shunting from right-to-left across the VSD. Ao = Aorta; LV = Left ventricle; MPA = Main pulmonary artery; RV = Right ventricle; RVOT = Right ventricular outflow tract. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.85 (a) RPS long-axis five-chamber echocardiogram of a Border Collie with tetralogy of Fallot. The aorta is overriding or dextraposed and a high VSD is present. (b) RPS short-axis view obtained at the level of the heart base and optimized for the RVOT. The pulmonic valve is stenotic and the valves are thickened and echogenic. The main pulmonary artery is hypoplastic. (c) RPS long-axis five-chamber view with colour Doppler. Blood is shunting from right-to-left across the VSD. Ao = Aorta; LV = Left ventricle; MPA = Main pulmonary artery; RV = Right ventricle; RVOT = Right ventricular outflow tract. (© J. Dukes-McEwan)

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7.86

(a) RPS short-axis view of a Domestic Shorthair cat with a tetralogy of Fallot. A high VSD is present and the colour flow map documents the right-to-left flow. (b) CW Doppler shows the right-to-left flow across the septal defect. LV = Left ventricle; RV = Right ventricle. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.86 (a) RPS short-axis view of a Domestic Shorthair cat with a tetralogy of Fallot. A high VSD is present and the colour flow map documents the right-to-left flow. (b) CW Doppler shows the right-to-left flow across the septal defect. LV = Left ventricle; RV = Right ventricle. (© J. Dukes-McEwan)

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7.87

Whole body composite left lateral static image of a 4-month-old English Bulldog obtained 5 minutes after intravenous injection of 99mTc-MAA. Notice the extrapulmonary distribution of the radiopharmaceutical, with marked uptake at the level of the renal cortices (arrowed), as well as the cerebral cortex (*); compare with Figure 7.54 . The diagnosis was tetralogy of Fallot. © 2008 British Small Animal Veterinary Association

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7.87 Whole body composite left lateral static image of a 4-month-old English Bulldog obtained 5 minutes after intravenous injection of 99mTc-MAA. Notice the extrapulmonary distribution of the radiopharmaceutical, with marked uptake at the level of the renal cortices (arrowed), as well as the cerebral cortex (*); compare with Figure 7.54 . The diagnosis was tetralogy of Fallot.

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7.88

Lateral view of the thorax of a dog with a PRAA. Note the gas accumulation in the cranial portion of the thoracic oesophagus (black arrow) on this survey radiograph. There is mineralized material in the cranioventral thorax (white arrow), which represents material accumulating in the distended oesophagus cranial to the vascular anomaly. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.88 Lateral view of the thorax of a dog with a PRAA. Note the gas accumulation in the cranial portion of the thoracic oesophagus (black arrow) on this survey radiograph. There is mineralized material in the cranioventral thorax (white arrow), which represents material accumulating in the distended oesophagus cranial to the vascular anomaly. (Courtesy of J. Buchanan)

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7.89

Lateral view of the thorax of a dog with a PRAA, after oral administration of barium sulphate. There is accumulation of the contrast medium in a distended oesophagus cranial to the heart base and abrupt tapering at the level of the heart base. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.89 Lateral view of the thorax of a dog with a PRAA, after oral administration of barium sulphate. There is accumulation of the contrast medium in a distended oesophagus cranial to the heart base and abrupt tapering at the level of the heart base. (Courtesy of J. Buchanan)

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7.90

Angiocardiogram in a dog with CTD. The contrast medium was injected in the CdVC. The RA is markedly dilated and there is a linear filling defect, corresponding to the dividing membrane (arrowed). CdVC = Caudal vena cava; RA Cd = Caudal section of the right atrium; RA Cr = Cranial section of the right atrium. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.90 Angiocardiogram in a dog with CTD. The contrast medium was injected in the CdVC. The RA is markedly dilated and there is a linear filling defect, corresponding to the dividing membrane (arrowed). CdVC = Caudal vena cava; RA Cd = Caudal section of the right atrium; RA Cr = Cranial section of the right atrium. (Courtesy of J. Buchanan)

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7.91

Angiocardiogram in a cat with CTS. The contrast medium was injected in the RV after catheterization of the jugular vein. A levophase image is presented, where the contrast medium has reached the left atrium (LA). The LA is enlarged and a linear filling defect is visible in its lumen, corresponding to the dividing membrane (arrowed). (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.91 Angiocardiogram in a cat with CTS. The contrast medium was injected in the RV after catheterization of the jugular vein. A levophase image is presented, where the contrast medium has reached the left atrium (LA). The LA is enlarged and a linear filling defect is visible in its lumen, corresponding to the dividing membrane (arrowed). (Courtesy of J. Buchanan)

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7.92

(a) Left apical four-chamber echocardiogram of a cat with an endocardial cushion defect and an unusual cor triatriatum. On this view the large confluent ASDs and VSDs are evident. (b) RPS long-axis view. The ASD can be seen and within the common atrium an additional thin dividing membrane is evident, creating an extra chamber (A*). This was considered to be a CTS; however, the decision as to whether the lesion is left- or right-sided is a difficult one when a common atrium is present. LA = Left atrium; LV = Left ventricle; RA = Right atrium; RV = Right ventricle. (© J. Dukes-McEwan) © 2008 British Small Animal Veterinary Association

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7.92 (a) Left apical four-chamber echocardiogram of a cat with an endocardial cushion defect and an unusual cor triatriatum. On this view the large confluent ASDs and VSDs are evident. (b) RPS long-axis view. The ASD can be seen and within the common atrium an additional thin dividing membrane is evident, creating an extra chamber (A*). This was considered to be a CTS; however, the decision as to whether the lesion is left- or right-sided is a difficult one when a common atrium is present. LA = Left atrium; LV = Left ventricle; RA = Right atrium; RV = Right ventricle. (© J. Dukes-McEwan)

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7.93

Lateral view of the thorax in a dog with aortic coarctation. Contrast medium was injected in the aortic arch after catheterization of the femoral artery. There is narrowing of the aorta distal to the origin of the left subclavian artery, followed by marked dilatation of the aorta after the stenosis. The catheter is seen curving around in the dilated portion of the aorta. (Courtesy of M. Herrtage) © 2008 British Small Animal Veterinary Association

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7.93 Lateral view of the thorax in a dog with aortic coarctation. Contrast medium was injected in the aortic arch after catheterization of the femoral artery. There is narrowing of the aorta distal to the origin of the left subclavian artery, followed by marked dilatation of the aorta after the stenosis. The catheter is seen curving around in the dilated portion of the aorta. (Courtesy of M. Herrtage)

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7.94

(a) Right lateral and (b) DV thoracic radiographs from a Cocker Spaniel, which presented with coughing and dyspnoea. There is generalized cardiomegaly with left atrial enlargement. Pulmonary venous distension is apparent. There is a mixed interstitial–alveolar infiltrate, consistent with pulmonary oedema. Echocardiography confirmed that this dog had DCM, resulting in the left-sided congestive heart failure. © 2008 British Small Animal Veterinary Association

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7.94 (a) Right lateral and (b) DV thoracic radiographs from a Cocker Spaniel, which presented with coughing and dyspnoea. There is generalized cardiomegaly with left atrial enlargement. Pulmonary venous distension is apparent. There is a mixed interstitial–alveolar infiltrate, consistent with pulmonary oedema. Echocardiography confirmed that this dog had DCM, resulting in the left-sided congestive heart failure.

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7.95

(a) Right lateral and (b) DV thoracic radiographs from a Dobermann, which presented with a history of several weeks coughing, recent syncopal episodes and then dyspnoea. DCM in the Dobermann is not associated with radiographic evidence of massive cardiomegaly, but there is left atrial and left ventricular enlargement. Note the pulmonary venous distension (arrowed) and the predominantly perihilar mixed interstitial and alveolar infiltrate. © 2008 British Small Animal Veterinary Association

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7.95 (a) Right lateral and (b) DV thoracic radiographs from a Dobermann, which presented with a history of several weeks coughing, recent syncopal episodes and then dyspnoea. DCM in the Dobermann is not associated with radiographic evidence of massive cardiomegaly, but there is left atrial and left ventricular enlargement. Note the pulmonary venous distension (arrowed) and the predominantly perihilar mixed interstitial and alveolar infiltrate.

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7.96

Calculation of the index of sphericity. (a) On a RPS long-axis view, every attempt is made to optimize the LV length. From a frozen image (diastolic frame: start of QRS complex), a measurement is taken from the mitral annulus to the apex of the LV. The diastolic LV length in this example is 77.8 mm. (b) The diastolic ‘width’ of the LV, at chordal level, is the M-mode diastolic chamber dimension (here 64.3 mm). In this example, the index of sphericity is the LV length (diastole)/LV width (diastole) = 77.8/64.3 = 1.21 (normal >1.7). The ventricle is confirmed as being abnormally rounded. © 2008 British Small Animal Veterinary Association

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7.96 Calculation of the index of sphericity. (a) On a RPS long-axis view, every attempt is made to optimize the LV length. From a frozen image (diastolic frame: start of QRS complex), a measurement is taken from the mitral annulus to the apex of the LV. The diastolic LV length in this example is 77.8 mm. (b) The diastolic ‘width’ of the LV, at chordal level, is the M-mode diastolic chamber dimension (here 64.3 mm). In this example, the index of sphericity is the LV length (diastole)/LV width (diastole) = 77.8/64.3 = 1.21 (normal >1.7). The ventricle is confirmed as being abnormally rounded.

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7.97

Simpson’s rule to calculate LV volume from a RPS long-axis four-chamber view. Every attempt should be made to optimize the LV chamber length and area. The LV chamber endocardium is traced around, closing at the mitral annulus, in both diastole and systole. A length from the mitral annulus to the LV apex is drawn. The ultrasound machine software divides this length into 20 divisions, considered as discs. The volume of each disc is calculated, and the sum of volumes of the discs gives the overall LV volume, relatively independent of geometrical assumptions. Both (a) end-diastolic volume (EDV) and (b) end-systolic volume (ESV) are calculated. The ejection fraction is calculated as (EDV–ESV)/EDV (usually expressed as a percentage) (normal >50%). The dog’s body surface area (BSA) can be calculated. The end-systolic volume index (ESVI) is the ESV/BSA (normal <30 ml/m2). The ejection fraction is low and the ESVI is increased in DCM, as in this Boxer. © 2008 British Small Animal Veterinary Association

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7.97 Simpson’s rule to calculate LV volume from a RPS long-axis four-chamber view. Every attempt should be made to optimize the LV chamber length and area. The LV chamber endocardium is traced around, closing at the mitral annulus, in both diastole and systole. A length from the mitral annulus to the LV apex is drawn. The ultrasound machine software divides this length into 20 divisions, considered as discs. The volume of each disc is calculated, and the sum of volumes of the discs gives the overall LV volume, relatively independent of geometrical assumptions. Both (a) end-diastolic volume (EDV) and (b) end-systolic volume (ESV) are calculated. The ejection fraction is calculated as (EDV–ESV)/EDV (usually expressed as a percentage) (normal >50%). The dog’s body surface area (BSA) can be calculated. The end-systolic volume index (ESVI) is the ESV/BSA (normal <30 ml/m2). The ejection fraction is low and the ESVI is increased in DCM, as in this Boxer.

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7.98

LV M-mode obtained from a Dobermann with DCM, indicating marked hypokinesis of the LV, proportionately thin walls and a dilated LV chamber. The LV diastolic and systolic measurements can be compared with reference values for breed, where known. This dog has atrial fibrillation. IVS = Interventricular septum; LV = Left ventricle; LVFW = Left ventricular free wall; RV = Right ventricle. © 2008 British Small Animal Veterinary Association

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7.98 LV M-mode obtained from a Dobermann with DCM, indicating marked hypokinesis of the LV, proportionately thin walls and a dilated LV chamber. The LV diastolic and systolic measurements can be compared with reference values for breed, where known. This dog has atrial fibrillation. IVS = Interventricular septum; LV = Left ventricle; LVFW = Left ventricular free wall; RV = Right ventricle.

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7.99

M-mode obtained at mitral valve level from a Leonberger with preclinical DCM. The anterior leaflet of the mitral valve (amv) moves towards the septum (IVS), and the posterior leaflet (pmv) moves towards the free wall of the LV (LVFW). In normal sinus rhythm, the amv opens twice in diastole: once early (E peak) corresponding to rapid LV filling, and once corresponding to atrial contraction (A peak). The E point to septal separation (EPSS) should not exceed 7 mm in any breed. It increases in DCM due to LV dilatation and rounding, and also because of reduced stroke volume. © 2008 British Small Animal Veterinary Association

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7.99 M-mode obtained at mitral valve level from a Leonberger with preclinical DCM. The anterior leaflet of the mitral valve (amv) moves towards the septum (IVS), and the posterior leaflet (pmv) moves towards the free wall of the LV (LVFW). In normal sinus rhythm, the amv opens twice in diastole: once early (E peak) corresponding to rapid LV filling, and once corresponding to atrial contraction (A peak). The E point to septal separation (EPSS) should not exceed 7 mm in any breed. It increases in DCM due to LV dilatation and rounding, and also because of reduced stroke volume.

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7.100

ARVC in a Boxer, which presented collapsed with ventricular tachycardia. The arrhythmia was treated. (a) RPS long-axis view and (b) short-axis view show dilatation of the RA and RV. (c) Apical sternal RPS view shows dysplastic papillary muscles in the RV apex (arrowed). Ao = Aorta; LA = Left atrium; LV = Left ventricle; RA = Right atrium; RV = Right ventricle. © 2008 British Small Animal Veterinary Association

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7.100 ARVC in a Boxer, which presented collapsed with ventricular tachycardia. The arrhythmia was treated. (a) RPS long-axis view and (b) short-axis view show dilatation of the RA and RV. (c) Apical sternal RPS view shows dysplastic papillary muscles in the RV apex (arrowed). Ao = Aorta; LA = Left atrium; LV = Left ventricle; RA = Right atrium; RV = Right ventricle.

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7.101

Images from a 2-year-old Border Terrier with frequent syncopal episodes of excitement and a heart murmur. A diagnosis was made of HOCM. There is marked concentric hypertrophy of the LV, evident from (a) the RPS long-axis four-chamber view, (b) the five-chamber view and (c) the short-axis view. There is no evidence of gross abnormality of the aortic valves, LVOT or the ascending aorta on the five-chamber view (b). However, in (b) the mitral valve anterior leaflet in this early systolic frame is shown moving towards the basal septum (*) (where endocardial thickening may be consistent with a ‘kissing’ lesion). (d) The presence of systolic anterior motion (SAM) of the anterior mitral valve leaflet (arrowed) is confirmed by the superior temporal resolution of M-mode at mitral valve level. SAM results in dynamic LVOT obstruction. (e) This can be documented from a left apical view. There is increased aortic outflow velocity with a biphasic acceleration slope (*). In this example, CW Doppler shows aortic peak velocities to be >6 m/s. (f) SAM also results in mitral valve incompetence and colour flow Doppler typically shows an eccentric MR jet, coursing towards the posterior-lateral wall of the LA. Ao = Aorta; IVS = Interventricular septum; LA = Left atrium; LV = Left ventricle; LVFW = Left ventricular free wall. © 2008 British Small Animal Veterinary Association

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7.101 Images from a 2-year-old Border Terrier with frequent syncopal episodes of excitement and a heart murmur. A diagnosis was made of HOCM. There is marked concentric hypertrophy of the LV, evident from (a) the RPS long-axis four-chamber view, (b) the five-chamber view and (c) the short-axis view. There is no evidence of gross abnormality of the aortic valves, LVOT or the ascending aorta on the five-chamber view (b). However, in (b) the mitral valve anterior leaflet in this early systolic frame is shown moving towards the basal septum (*) (where endocardial thickening may be consistent with a ‘kissing’ lesion). (d) The presence of systolic anterior motion (SAM) of the anterior mitral valve leaflet (arrowed) is confirmed by the superior temporal resolution of M-mode at mitral valve level. SAM results in dynamic LVOT obstruction. (e) This can be documented from a left apical view. There is increased aortic outflow velocity with a biphasic acceleration slope (*). In this example, CW Doppler shows aortic peak velocities to be >6 m/s. (f) SAM also results in mitral valve incompetence and colour flow Doppler typically shows an eccentric MR jet, coursing towards the posterior-lateral wall of the LA. Ao = Aorta; IVS = Interventricular septum; LA = Left atrium; LV = Left ventricle; LVFW = Left ventricular free wall.

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7.102

(a) Right lateral and (b) DV thoracic radiographs from a cat, which presented with apparently sudden onset left-sided congestive heart failure. There is marked left atrial enlargement and dilatation of the LAu, which on the DV view results in the appearance of a ‘valentine heart’. Both pulmonary arteries and veins are dilated (pulmonary hypertension may be secondary to left-sided failure in the cat). The pulmonary infiltrate associated with cardiogenic pulmonary oedema in the cat can be patchy and variable in distribution, as indicated here. This cat also has radiographic evidence of pericardial fat. © 2008 British Small Animal Veterinary Association

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7.102 (a) Right lateral and (b) DV thoracic radiographs from a cat, which presented with apparently sudden onset left-sided congestive heart failure. There is marked left atrial enlargement and dilatation of the LAu, which on the DV view results in the appearance of a ‘valentine heart’. Both pulmonary arteries and veins are dilated (pulmonary hypertension may be secondary to left-sided failure in the cat). The pulmonary infiltrate associated with cardiogenic pulmonary oedema in the cat can be patchy and variable in distribution, as indicated here. This cat also has radiographic evidence of pericardial fat.

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7.104

Images from a 2-year-old British Shorthair cat with HCM. There is marked concentric hypertrophy of the LV. (a) The basal septal bulge may result in turbulence or increased velocity of LV outflow. If the basal septal bulge exceeds 6 mm in diastole, this confirms the presence of significant hypertrophy. (b) A short-axis view can be used to measure wall thickness at the chordal level, ensuring that papillary muscles are not inadvertently included. Diastolic wall thicknesses over 6 mm confirm hypertrophy, as here. (c) The M-mode in feline HCM typically has a cluttered appearance, particularly at mitral valve level. Ao = Aorta; IVS = Interventricular septum; LA = Left atrium; LVFW = Left ventricular free wall. © 2008 British Small Animal Veterinary Association

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7.104 Images from a 2-year-old British Shorthair cat with HCM. There is marked concentric hypertrophy of the LV. (a) The basal septal bulge may result in turbulence or increased velocity of LV outflow. If the basal septal bulge exceeds 6 mm in diastole, this confirms the presence of significant hypertrophy. (b) A short-axis view can be used to measure wall thickness at the chordal level, ensuring that papillary muscles are not inadvertently included. Diastolic wall thicknesses over 6 mm confirm hypertrophy, as here. (c) The M-mode in feline HCM typically has a cluttered appearance, particularly at mitral valve level. Ao = Aorta; IVS = Interventricular septum; LA = Left atrium; LVFW = Left ventricular free wall.

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7.105

Left atrial dilatation is a consequence of significant diastolic dysfunction and elevated filling pressures in the cat. In cats with asymptomatic HCM, the left atrial size may still be normal. From a RPS long-axis four-chamber view, the maximum width of the LA, parallel to the mitral annulus, can be measured (normal <16 mm). © 2008 British Small Animal Veterinary Association

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7.105 Left atrial dilatation is a consequence of significant diastolic dysfunction and elevated filling pressures in the cat. In cats with asymptomatic HCM, the left atrial size may still be normal. From a RPS long-axis four-chamber view, the maximum width of the LA, parallel to the mitral annulus, can be measured (normal <16 mm).

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7.106

This is the same cat as in Figure 7.104 . The LA is grossly dilated, both measured from (a) a RPS long-axis four-chamber view and (b) assessing the 2D short-axis LA:aortic root ratio in diastole. The ratio is 2.55 (normal <1.5). LA = Left atrium; LAu = Left auricular appendage; RA = Right atrium; RVOT = Right ventricular outflow tract. © 2008 British Small Animal Veterinary Association

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7.106 This is the same cat as in Figure 7.104 . The LA is grossly dilated, both measured from (a) a RPS long-axis four-chamber view and (b) assessing the 2D short-axis LA:aortic root ratio in diastole. The ratio is 2.55 (normal <1.5). LA = Left atrium; LAu = Left auricular appendage; RA = Right atrium; RVOT = Right ventricular outflow tract.

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7.107

M-mode of a cat with HCM, showing the concentric hypertrophy and the apparent hyperkinesis of the LV. IVS = Interventricular septum; LVFW = Left ventricular free wall. © 2008 British Small Animal Veterinary Association

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7.107 M-mode of a cat with HCM, showing the concentric hypertrophy and the apparent hyperkinesis of the LV. IVS = Interventricular septum; LVFW = Left ventricular free wall.

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7.108

Evidence of dynamic LVOT obstruction due to systolic anterior motion (SAM) of the anterior mitral valve leaflet, leads to the diagnosis of HOCM. (a) There is increased and turbulent LVOT velocity, with a biphasic acceleration slope (so-called ‘scimitar’ shape); in this example the aortic outflow velocity is around 4 m/s. (b) RPS long-axis five-chamber view. The presence of SAM leads to mitral incompetence, with an eccentric mitral regurgitant jet coursing towards the posterior–lateral wall of the LA, as well as colour variance in the LVOT. (c) SAM is best confirmed by mitral M-mode. © 2008 British Small Animal Veterinary Association

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7.108 Evidence of dynamic LVOT obstruction due to systolic anterior motion (SAM) of the anterior mitral valve leaflet, leads to the diagnosis of HOCM. (a) There is increased and turbulent LVOT velocity, with a biphasic acceleration slope (so-called ‘scimitar’ shape); in this example the aortic outflow velocity is around 4 m/s. (b) RPS long-axis five-chamber view. The presence of SAM leads to mitral incompetence, with an eccentric mitral regurgitant jet coursing towards the posterior–lateral wall of the LA, as well as colour variance in the LVOT. (c) SAM is best confirmed by mitral M-mode.

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7.110

Mitral inflow patterns. (a) Normal mitral inflow with E wave velocity <2 but >1 × A wave velocity. (b) Abnormal relaxation. As active relaxation (lusitropy) of the LV is compromised, E wave velocity is reduced and E wave deceleration time is prolonged. IVRT is prolonged. Atrial contraction is important to achieve ventricular filling. A>E wave velocities. (c) With evolution of the disease, left atrial pressures increase and E wave velocity increases, giving a relatively normal E:A ratio again (pseudonormalization). (d) Further worsening of the disease, with high left atrial pressure and a stiff, poorly compliant LV, can result in a high E wave velocity, short E wave deceleration time and E:A velocity ratio of >2 (restrictive filling pattern). © 2008 British Small Animal Veterinary Association

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7.110 Mitral inflow patterns. (a) Normal mitral inflow with E wave velocity <2 but >1 × A wave velocity. (b) Abnormal relaxation. As active relaxation (lusitropy) of the LV is compromised, E wave velocity is reduced and E wave deceleration time is prolonged. IVRT is prolonged. Atrial contraction is important to achieve ventricular filling. A>E wave velocities. (c) With evolution of the disease, left atrial pressures increase and E wave velocity increases, giving a relatively normal E:A ratio again (pseudonormalization). (d) Further worsening of the disease, with high left atrial pressure and a stiff, poorly compliant LV, can result in a high E wave velocity, short E wave deceleration time and E:A velocity ratio of >2 (restrictive filling pattern).

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7.111

Mitral inflow patterns from cats with myocardial disease. (a) A cat with HOCM, which presented for investigation of an asymptomatic heart murmur. Note the abnormal relaxation pattern (E<A; prolonged E deceleration time). (b) Re-evaluation 6 months later. The cat was still asymptomatic but there is evidence of increased LA pressure; the E wave velocity is increased, although, there is still E:A reversal and evidence of abnormal relaxation. (c) A cat with pseudonormalization. Note that although the LA pressures have increased, the abnormal relaxation is now masked, and other methods are required to document the diastolic dysfunction. (d) A cat with severe biventricular failure and a RCM. A restrictive filling pattern with probable LA dysfunction is shown, with E>>A, low velocity A wave and short E wave deceleration time. © 2008 British Small Animal Veterinary Association

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7.111 Mitral inflow patterns from cats with myocardial disease. (a) A cat with HOCM, which presented for investigation of an asymptomatic heart murmur. Note the abnormal relaxation pattern (E<A; prolonged E deceleration time). (b) Re-evaluation 6 months later. The cat was still asymptomatic but there is evidence of increased LA pressure; the E wave velocity is increased, although, there is still E:A reversal and evidence of abnormal relaxation. (c) A cat with pseudonormalization. Note that although the LA pressures have increased, the abnormal relaxation is now masked, and other methods are required to document the diastolic dysfunction. (d) A cat with severe biventricular failure and a RCM. A restrictive filling pattern with probable LA dysfunction is shown, with E>>A, low velocity A wave and short E wave deceleration time.

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7.112

Measurement of IVRT in cats with myocardial disease. (a) Normal cat, with time measurement from aortic valve closure to onset of mitral flow. (b) A cat with abnormal relaxation time, showing increased IVRT (>65 ms). (c) A cat with a restrictive filling time, showing very short IVRT (<55 ms). © 2008 British Small Animal Veterinary Association

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7.112 Measurement of IVRT in cats with myocardial disease. (a) Normal cat, with time measurement from aortic valve closure to onset of mitral flow. (b) A cat with abnormal relaxation time, showing increased IVRT (>65 ms). (c) A cat with a restrictive filling time, showing very short IVRT (<55 ms).

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7.113

Assessment of PVF pattern in cats with myocardial disease. (a) Normal, middle-aged cat with D>S. (b) A cat with abnormal relaxation, with increased S wave (measurement 2) and lower D wave (measurement 3) velocity, but increased velocity of the Ar wave (measurement 1). (c) A cat with a restrictive filling pattern, with normal atrial function (increased Ar wave). D wave velocity exceeds S, and D deceleration is rapid. © 2008 British Small Animal Veterinary Association

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7.113 Assessment of PVF pattern in cats with myocardial disease. (a) Normal, middle-aged cat with D>S. (b) A cat with abnormal relaxation, with increased S wave (measurement 2) and lower D wave (measurement 3) velocity, but increased velocity of the Ar wave (measurement 1). (c) A cat with a restrictive filling pattern, with normal atrial function (increased Ar wave). D wave velocity exceeds S, and D deceleration is rapid.

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7.114

Marked left atrial enlargement is apparent in this example of a RCM, both from (a) the RPS long-axis four-chamber view (33 mm diameter) and (b) the RPS short-axis view at the level of the aortic valves. In the short-axis view, there is a poorly defined thrombus in the LAu with a real-time image showing spontaneous echocontrast in the LA. This cat had atrial fibrillation with occasional ventricular premature complexes. (c) A modified LPS cranial view, optimized for the LAu. The thrombus in the LAu can be seen with spontaneous echocontrast appearing as ‘smoke’, swirling in the junction of the LAu and LA. (d) RPS four-chamber view of the LV showing an irregular endocardium, particularly on the septum, and a probable adhesion crossing the LV chamber. Ao = Aorta; LA = Left atrium; LV = Left ventricle; MV = Mitral valve; RA = Right atrium; RV = Right ventricle; RVOT = Right ventricular outflow tract. © 2008 British Small Animal Veterinary Association

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7.114 Marked left atrial enlargement is apparent in this example of a RCM, both from (a) the RPS long-axis four-chamber view (33 mm diameter) and (b) the RPS short-axis view at the level of the aortic valves. In the short-axis view, there is a poorly defined thrombus in the LAu with a real-time image showing spontaneous echocontrast in the LA. This cat had atrial fibrillation with occasional ventricular premature complexes. (c) A modified LPS cranial view, optimized for the LAu. The thrombus in the LAu can be seen with spontaneous echocontrast appearing as ‘smoke’, swirling in the junction of the LAu and LA. (d) RPS four-chamber view of the LV showing an irregular endocardium, particularly on the septum, and a probable adhesion crossing the LV chamber. Ao = Aorta; LA = Left atrium; LV = Left ventricle; MV = Mitral valve; RA = Right atrium; RV = Right ventricle; RVOT = Right ventricular outflow tract.

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7.115

(a) Right lateral and (b) DV thoracic radiographs from a cat with DCM. There is a significant pleural effusion, masking detail of the cardiac silhouette and the lung fields. From the degree of tracheal elevation, the cardiac silhouette appears to show marked generalized enlargement. © 2008 British Small Animal Veterinary Association

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7.115 (a) Right lateral and (b) DV thoracic radiographs from a cat with DCM. There is a significant pleural effusion, masking detail of the cardiac silhouette and the lung fields. From the degree of tracheal elevation, the cardiac silhouette appears to show marked generalized enlargement.

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7.116

M-mode of a cat with DCM from 1988, showing a pleural effusion and marked hypokinesis, especially of the left ventricular free wall (LVFW). IVS = Interventricular septum; LV = Left ventricle. © 2008 British Small Animal Veterinary Association

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7.116 M-mode of a cat with DCM from 1988, showing a pleural effusion and marked hypokinesis, especially of the left ventricular free wall (LVFW). IVS = Interventricular septum; LV = Left ventricle.

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7.117

Images from an elderly cat with untreated, probably long-standing, hyperthyroidism. (a) The RPS long-axis four-chamber view shows four-chamber dilatation. (b) In real time, the LV was noticeably hypokinetic, which is indicated on the M-mode. Notice that the left ventricular free wall (LVFW) is not functioning on the M-mode, and the wall is thin. A segmental region of posterior wall thinning, corresponding to the M-mode sampling, is shown in (a) (*). This may correspond to a myocardial infarct (although postmortem confirmation was not achieved in this cat). IVS = Interventricular septum. © 2008 British Small Animal Veterinary Association

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7.117 Images from an elderly cat with untreated, probably long-standing, hyperthyroidism. (a) The RPS long-axis four-chamber view shows four-chamber dilatation. (b) In real time, the LV was noticeably hypokinetic, which is indicated on the M-mode. Notice that the left ventricular free wall (LVFW) is not functioning on the M-mode, and the wall is thin. A segmental region of posterior wall thinning, corresponding to the M-mode sampling, is shown in (a) (*). This may correspond to a myocardial infarct (although postmortem confirmation was not achieved in this cat). IVS = Interventricular septum.

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7.118

(a) Right lateral radiograph from a cat later confirmed to have ARVC. Ascites with the dilated CdVC indicates radiographic support for right-sided congestive heart failure. From this view (no DV available) there appears to be predominantly right-sided enlargement, resulting in cardiomegaly. (b) RPS long-axis four-chamber view, indicating marked right atrial and right ventricular enlargement. © 2008 British Small Animal Veterinary Association

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7.118 (a) Right lateral radiograph from a cat later confirmed to have ARVC. Ascites with the dilated CdVC indicates radiographic support for right-sided congestive heart failure. From this view (no DV available) there appears to be predominantly right-sided enlargement, resulting in cardiomegaly. (b) RPS long-axis four-chamber view, indicating marked right atrial and right ventricular enlargement.

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7.119

(a) RPS long-axis four-chamber view of a cat with ARVC. Colour flow mapping indicates the presence of tricuspid and mitral regurgitation due to stretch of the atrioventricular annuli, secondary to myocardial disease, although the RV is predominantly affected. (b) M-mode, showing dilatation of both ventricles and impaired LV systolic function. This cat was in atrial fibrillation. © 2008 British Small Animal Veterinary Association

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7.119 (a) RPS long-axis four-chamber view of a cat with ARVC. Colour flow mapping indicates the presence of tricuspid and mitral regurgitation due to stretch of the atrioventricular annuli, secondary to myocardial disease, although the RV is predominantly affected. (b) M-mode, showing dilatation of both ventricles and impaired LV systolic function. This cat was in atrial fibrillation.

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7.120

(a) The RPS long-axis four-chamber view and (b) M-mode, including the mitral valve, show mild chamber dilatation and impaired LV systolic function. There is also a restrictive filling pattern. This cat was categorized as having an UCM. This cat was also in atrial fibrillation. © 2008 British Small Animal Veterinary Association

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7.120 (a) The RPS long-axis four-chamber view and (b) M-mode, including the mitral valve, show mild chamber dilatation and impaired LV systolic function. There is also a restrictive filling pattern. This cat was categorized as having an UCM. This cat was also in atrial fibrillation.

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7.121

(a) Right lateral and (b) DV thoracic radiographs from a Cavalier King Charles Spaniel with presumed idiopathic (essential) pulmonary hypertension, as other common causes of pulmonary hypertension had been actively excluded. There is marked right-sided enlargement, resulting in generalized cardiomegaly. (The DV view is slightly rotated.) © 2008 British Small Animal Veterinary Association

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7.121 (a) Right lateral and (b) DV thoracic radiographs from a Cavalier King Charles Spaniel with presumed idiopathic (essential) pulmonary hypertension, as other common causes of pulmonary hypertension had been actively excluded. There is marked right-sided enlargement, resulting in generalized cardiomegaly. (The DV view is slightly rotated.)

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7.122

(a) Right lateral and (b) DV thoracic radiographs from a West Highland White Terrier with idiopathic pulmonary fibrosis and echocardiographically confirmed pulmonary hypertension. The radiographs show mild right heart enlargement. The cardiac silhouette and pulmonary vasculature are masked by a gross, generalized, interstitial opacity throughout the lung fields. © 2008 British Small Animal Veterinary Association

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7.122 (a) Right lateral and (b) DV thoracic radiographs from a West Highland White Terrier with idiopathic pulmonary fibrosis and echocardiographically confirmed pulmonary hypertension. The radiographs show mild right heart enlargement. The cardiac silhouette and pulmonary vasculature are masked by a gross, generalized, interstitial opacity throughout the lung fields.

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7.123

(a) Right lateral and (b) DV thoracic radiographs from a dog with Dirofilaria immitis infection (heartworm). The pulmonary arteries are markedly dilated and tortuous (arrowed). (Courtesy of M. Sullivan) © 2008 British Small Animal Veterinary Association

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7.123 (a) Right lateral and (b) DV thoracic radiographs from a dog with Dirofilaria immitis infection (heartworm). The pulmonary arteries are markedly dilated and tortuous (arrowed). (Courtesy of M. Sullivan)

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7.124

Images from a 5-year-old Cavalier King Charles Spaniel with a PDA associated with pulmonary hypertension, presented with ascites and other evidence of right-sided congestive heart failure. (a) RPS long-axis four-chamber view shows marked right atrial and right ventricular dilatation, with concentric hypertrophy of the RV wall. The IVS is flattened, which is also appreciated on (b) the RPS short-axis view. The right branch of the pulmonary artery (RPA) is also markedly dilated as it courses around the base of the heart. (c) The RPS cranial view shows the dilated pulmonary trunk with marked pulmonary insufficiency. (d) The left apical four-chamber view shows tricuspid regurgitation by colour flow Doppler. (e) Mean CW Doppler recorded velocity of the tricuspid regurgitant jet is 4.6 m/s. By the modified Bernoulli equation, there is a systolic PG (4v2) between the RV and RA of 84 mmHg. Therefore, pulmonary arterial systolic pressure is at least 90 mmHg (since normal right atrial pressure is about 6 mmHg). (f) The mean velocity of pulmonary regurgitation is 3.4 m/s (recorded from a RPS cranial view). Therefore, the diastolic PG between the main pulmonary artery and RV is 46 mmHg. Thus, the systolic/diastolic pulmonary pressures are estimated to be at least 90/46 mmHg (but this is an underestimate as the dog is in right-sided failure; RA and RV filling pressures will be increased). This has an impact on the PDA flow. There is some left-to-right diastolic flow but in systole, no flow was evident (‘balanced’ PDA as a consequence of the pulmonary hypertension). Ao = Aorta; LA = Left atrium; LV = Left ventricle; RA = Right atrium; RV = Right ventricle; RVOT = Right ventricular outflow tract. © 2008 British Small Animal Veterinary Association

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7.124 Images from a 5-year-old Cavalier King Charles Spaniel with a PDA associated with pulmonary hypertension, presented with ascites and other evidence of right-sided congestive heart failure. (a) RPS long-axis four-chamber view shows marked right atrial and right ventricular dilatation, with concentric hypertrophy of the RV wall. The IVS is flattened, which is also appreciated on (b) the RPS short-axis view. The right branch of the pulmonary artery (RPA) is also markedly dilated as it courses around the base of the heart. (c) The RPS cranial view shows the dilated pulmonary trunk with marked pulmonary insufficiency. (d) The left apical four-chamber view shows tricuspid regurgitation by colour flow Doppler. (e) Mean CW Doppler recorded velocity of the tricuspid regurgitant jet is 4.6 m/s. By the modified Bernoulli equation, there is a systolic PG (4v2) between the RV and RA of 84 mmHg. Therefore, pulmonary arterial systolic pressure is at least 90 mmHg (since normal right atrial pressure is about 6 mmHg). (f) The mean velocity of pulmonary regurgitation is 3.4 m/s (recorded from a RPS cranial view). Therefore, the diastolic PG between the main pulmonary artery and RV is 46 mmHg. Thus, the systolic/diastolic pulmonary pressures are estimated to be at least 90/46 mmHg (but this is an underestimate as the dog is in right-sided failure; RA and RV filling pressures will be increased). This has an impact on the PDA flow. There is some left-to-right diastolic flow but in systole, no flow was evident (‘balanced’ PDA as a consequence of the pulmonary hypertension). Ao = Aorta; LA = Left atrium; LV = Left ventricle; RA = Right atrium; RV = Right ventricle; RVOT = Right ventricular outflow tract.

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7.125

(a) RPS long-axis four-chamber view and (b) short-axis view from a crossbred dog. The myocardium appears thickened but with a heterogenous patchy increased echogenicity. There is a small amount of pericardial effusion. This was sampled and cytology confirmed the diagnosis of cardiac lymphoma. (c) After 9 days of staged chemotherapy, reduction in the thickness of the walls could be seen. © 2008 British Small Animal Veterinary Association

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7.125 (a) RPS long-axis four-chamber view and (b) short-axis view from a crossbred dog. The myocardium appears thickened but with a heterogenous patchy increased echogenicity. There is a small amount of pericardial effusion. This was sampled and cytology confirmed the diagnosis of cardiac lymphoma. (c) After 9 days of staged chemotherapy, reduction in the thickness of the walls could be seen.

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7.126

Images from an 11-year-old male Golden Retriever, which presented collapsed, anaemic and with paroxysmal ventricular tachycardia. (a) The RPS long-axis four-chamber view, (b) short-axis view and (c) left apical four-chamber view all show evidence of thickened myocardial walls, with disrupted architecture, and numerous hypoechoic lesions of various sizes. (d) Postmortem examination showed the entire myocardium was affected by a disseminated haemangiosarcoma. LA = Left atrium; LV = Left ventricle; RV = Right ventricle. (Courtesy of R. Irvine) © 2008 British Small Animal Veterinary Association

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7.126 Images from an 11-year-old male Golden Retriever, which presented collapsed, anaemic and with paroxysmal ventricular tachycardia. (a) The RPS long-axis four-chamber view, (b) short-axis view and (c) left apical four-chamber view all show evidence of thickened myocardial walls, with disrupted architecture, and numerous hypoechoic lesions of various sizes. (d) Postmortem examination showed the entire myocardium was affected by a disseminated haemangiosarcoma. LA = Left atrium; LV = Left ventricle; RV = Right ventricle. (Courtesy of R. Irvine)

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7.128

A series of five lateral radiographs obtained over a period of 4 years in a middle-aged Cavalier King Charles Spaniel with confirmed endocardiosis. (a) Normal. The initial view was obtained when a soft systolic murmur consistent with mitral regurgitation was detected on clinical examination. No significant abnormalities are present on this film. The disease progressed over the following 4 years and left-sided and eventually generalized cardiomegaly developed. (b) Slight cardiomegaly. (c) Moderate cardiomegaly. (d) Moderate cardiomegaly and congestive heart failure. Note that left-sided heart failure and a perihilar alveolar infiltrate are evident on this film. (e) Severe cardiomegaly and congestive heart failure. The heart failure was treated but recurred. © 2008 British Small Animal Veterinary Association

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7.128 A series of five lateral radiographs obtained over a period of 4 years in a middle-aged Cavalier King Charles Spaniel with confirmed endocardiosis. (a) Normal. The initial view was obtained when a soft systolic murmur consistent with mitral regurgitation was detected on clinical examination. No significant abnormalities are present on this film. The disease progressed over the following 4 years and left-sided and eventually generalized cardiomegaly developed. (b) Slight cardiomegaly. (c) Moderate cardiomegaly. (d) Moderate cardiomegaly and congestive heart failure. Note that left-sided heart failure and a perihilar alveolar infiltrate are evident on this film. (e) Severe cardiomegaly and congestive heart failure. The heart failure was treated but recurred.

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7.129

RPS long-axis echocardiogram, optimized for visualization of the mitral valve in a dog with myxomatous mitral valve degeneration. A thickened region is present at the tips of both valve leaflets creating a ‘club-like’ appearance (arrows show the thickened region on the septal leaflet). LA = Left atrium; LV = Left ventricle. © 2008 British Small Animal Veterinary Association

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7.129 RPS long-axis echocardiogram, optimized for visualization of the mitral valve in a dog with myxomatous mitral valve degeneration. A thickened region is present at the tips of both valve leaflets creating a ‘club-like’ appearance (arrows show the thickened region on the septal leaflet). LA = Left atrium; LV = Left ventricle.

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7.130

A flail leaflet is seen in this dog with myxomatous mitral valve degeneration. Note that the septal leaflet is displaced above the level of the valve annulus. This image was acquired during systole. LA = Left atrium; LV = Left ventricle. © 2008 British Small Animal Veterinary Association

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7.130 A flail leaflet is seen in this dog with myxomatous mitral valve degeneration. Note that the septal leaflet is displaced above the level of the valve annulus. This image was acquired during systole. LA = Left atrium; LV = Left ventricle.

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7.131

RPS short-axis view at the heart base in a dog with myxomatous mitral valve degeneration. Normally the ratio of left atrium (LA) to aortic (Ao) diameter at this level should be no greater than 1.5:1; in this case the atrium is enlarged. The size of the LA is an important indicator of disease severity. © 2008 British Small Animal Veterinary Association

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7.131 RPS short-axis view at the heart base in a dog with myxomatous mitral valve degeneration. Normally the ratio of left atrium (LA) to aortic (Ao) diameter at this level should be no greater than 1.5:1; in this case the atrium is enlarged. The size of the LA is an important indicator of disease severity.

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7.132

An M-mode echocardiogram obtained from a RPS short-axis view at the level of the papillary muscles. Note the hyperkinetic motion of the IVS, secondary to the rapid regurgitation of left ventricular blood into the low pressure LA during systole. IVS = Interventricular septum; LV = Left ventricle; LVFW = Left ventricular free wall; PM = Edge of papillary muscle that was included in the image. © 2008 British Small Animal Veterinary Association

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7.132 An M-mode echocardiogram obtained from a RPS short-axis view at the level of the papillary muscles. Note the hyperkinetic motion of the IVS, secondary to the rapid regurgitation of left ventricular blood into the low pressure LA during systole. IVS = Interventricular septum; LV = Left ventricle; LVFW = Left ventricular free wall; PM = Edge of papillary muscle that was included in the image.

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7.133

Colour and spectral Doppler echocardiograms of two dogs with myxomatous mitral valve disease. (a) A large jet of mitral regurgitation, extending to the wall of the LA. (b) CW spectral Doppler tracing from a dog with mitral regurgitation. The cursor was placed in the mitral regurgitant jet. LA = Left atrium; LV = Left ventricle; MR = Mitral regurgitation. © 2008 British Small Animal Veterinary Association

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7.133 Colour and spectral Doppler echocardiograms of two dogs with myxomatous mitral valve disease. (a) A large jet of mitral regurgitation, extending to the wall of the LA. (b) CW spectral Doppler tracing from a dog with mitral regurgitation. The cursor was placed in the mitral regurgitant jet. LA = Left atrium; LV = Left ventricle; MR = Mitral regurgitation.

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7.134

(a) Long-axis RPS view of a mixed breed dog with bacterial endocarditis of the mitral valve, secondary to a snake bite. Large florid masses are present on the valve leaflets. (b) Short-axis RPS view of a mixed breed dog with bacterial endocarditis of the mitral valve, secondary to a snake bite. Large florid masses are present on the valve leaflets. LA = Left atrium; LV = Left ventricle. © 2008 British Small Animal Veterinary Association

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7.134 (a) Long-axis RPS view of a mixed breed dog with bacterial endocarditis of the mitral valve, secondary to a snake bite. Large florid masses are present on the valve leaflets. (b) Short-axis RPS view of a mixed breed dog with bacterial endocarditis of the mitral valve, secondary to a snake bite. Large florid masses are present on the valve leaflets. LA = Left atrium; LV = Left ventricle.

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7.135

RPS short-axis echocardiogram at the heart base. A flame-like small jet of pulmonic insufficiency was identified in this 2-year-old Flat Coated Retriever. This was considered to be a clinically insignificant finding. The pulmonic valve and outflow velocity were normal. MPA = Main pulmonary artery; RVOT = Right ventricular outflow tract. © 2008 British Small Animal Veterinary Association

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7.135 RPS short-axis echocardiogram at the heart base. A flame-like small jet of pulmonic insufficiency was identified in this 2-year-old Flat Coated Retriever. This was considered to be a clinically insignificant finding. The pulmonic valve and outflow velocity were normal. MPA = Main pulmonary artery; RVOT = Right ventricular outflow tract.

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7.136

A tiny jet of aortic insufficiency identified on a RPS long-axis view (optimized for the aorta) in a 7-year-old Border Collie cross breed dog. This insufficiency was considered to be a clinically insignificant finding. Ao = Aorta; LV = Left ventricle. © 2008 British Small Animal Veterinary Association

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7.136 A tiny jet of aortic insufficiency identified on a RPS long-axis view (optimized for the aorta) in a 7-year-old Border Collie cross breed dog. This insufficiency was considered to be a clinically insignificant finding. Ao = Aorta; LV = Left ventricle.

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7.137

Echocardiographic and postmortem images of the heart of a 5-year-old male Labrador Retriever. The dog fell heavily on to a gate whilst jumping and developed an acute onset grade 5 holosystolic murmur and pulmonary oedema. (a) RPS long-axis view of the heart during diastole, showing separation of the free wall mitral leaflet from the valve annulus. The white arrow shows the direction of blood through the tear. (b) Colour Doppler revealed an eccentric jet of mitral regurgitation through this region. (c) At postmortem a mitral valve avulsion and left atrial dissecting aneurysm were confirmed. The tear separating the leaflet from the valve annulus was identified. LA = Left atrium; LV = Left ventricle. (Courtesy of P. Wotton) © 2008 British Small Animal Veterinary Association

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7.137 Echocardiographic and postmortem images of the heart of a 5-year-old male Labrador Retriever. The dog fell heavily on to a gate whilst jumping and developed an acute onset grade 5 holosystolic murmur and pulmonary oedema. (a) RPS long-axis view of the heart during diastole, showing separation of the free wall mitral leaflet from the valve annulus. The white arrow shows the direction of blood through the tear. (b) Colour Doppler revealed an eccentric jet of mitral regurgitation through this region. (c) At postmortem a mitral valve avulsion and left atrial dissecting aneurysm were confirmed. The tear separating the leaflet from the valve annulus was identified. LA = Left atrium; LV = Left ventricle. (Courtesy of P. Wotton)

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7.138

DV radiograph of a dog with a large volume pericardial effusion. Note the extremely sharp margins of the cardiac silhouette. This is often a clue to the presence of a pericardial effusion in a dog with globoid cardiomegaly. © 2008 British Small Animal Veterinary Association

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7.138 DV radiograph of a dog with a large volume pericardial effusion. Note the extremely sharp margins of the cardiac silhouette. This is often a clue to the presence of a pericardial effusion in a dog with globoid cardiomegaly.

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7.139

RPS long-axis echocardiogram of a 7-year-old Golden Retriever with pericardial effusion. The effusion was identified as an anechoic region (PE) surrounding the heart and encased by a thin hyperechoic rim of pericardium (arrowed). A small volume pleural effusion was also present in this dog in association with right-sided heart failure. This is seen as an anechoic region surrounding a collapsed lung lobe tip (L) in the foreground. © 2008 British Small Animal Veterinary Association

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7.139 RPS long-axis echocardiogram of a 7-year-old Golden Retriever with pericardial effusion. The effusion was identified as an anechoic region (PE) surrounding the heart and encased by a thin hyperechoic rim of pericardium (arrowed). A small volume pleural effusion was also present in this dog in association with right-sided heart failure. This is seen as an anechoic region surrounding a collapsed lung lobe tip (L) in the foreground.

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7.140

A pericardial effusion can produce cardiac tamponade. (a) RPS short-axis echocardiogram at the level of the papillary muscles in a dog with a pericardial effusion (PE). The image was obtained during diastole and the RV shows collapse (arrowed) due to the pericardial pressure exceeding the intraventricular pressure. This confirms cardiac tamponade. A small pleural effusion was also present in this dog (*). (b) RPS short-axis echocardiogram at the level of the papillary muscles in another dog with pericardial effusion. This dog does not show any evidence of tamponade as the RV did not collapse during diastole. Note that the atria should also be examined for evidence of collapse indicating tamponade. © 2008 British Small Animal Veterinary Association

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7.140 A pericardial effusion can produce cardiac tamponade. (a) RPS short-axis echocardiogram at the level of the papillary muscles in a dog with a pericardial effusion (PE). The image was obtained during diastole and the RV shows collapse (arrowed) due to the pericardial pressure exceeding the intraventricular pressure. This confirms cardiac tamponade. A small pleural effusion was also present in this dog (*). (b) RPS short-axis echocardiogram at the level of the papillary muscles in another dog with pericardial effusion. This dog does not show any evidence of tamponade as the RV did not collapse during diastole. Note that the atria should also be examined for evidence of collapse indicating tamponade.

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7.141

It is extremely important to visualize the tip of the right auricular appendage (RAu) when evaluating patients for neoplastic causes of pericardial effusion. No mass was identified in this dog (compare with Figure 7.149 ). The auricular wall is thickened and slightly irregular. This is a RPS view of the heart base optimized for the RAu. LPS cranial views are also useful to examine the RAu. © 2008 British Small Animal Veterinary Association

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7.141 It is extremely important to visualize the tip of the right auricular appendage (RAu) when evaluating patients for neoplastic causes of pericardial effusion. No mass was identified in this dog (compare with Figure 7.149 ). The auricular wall is thickened and slightly irregular. This is a RPS view of the heart base optimized for the RAu. LPS cranial views are also useful to examine the RAu.

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7.142

It is very important to perform a thorough examination in order to identify heart base masses. They often surround the ascending aorta; this is a difficult area to assess due to the surrounding air-filled lung. (a) RPS short-axis view of the heart base showing the aorta (Ao) and main pulmonary artery (MPA). The operator should continue to obtain views more dorsally from this location (until imaging is no longer possible) in a search for a heart base mass. This dog had a pericardial effusion (PE) but no mass was identified. (b) LPS four-chamber view. It is important to obtain LPS views and optimize imaging for the heart base (in the far field). No mass was identified in this dog. © 2008 British Small Animal Veterinary Association

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7.142 It is very important to perform a thorough examination in order to identify heart base masses. They often surround the ascending aorta; this is a difficult area to assess due to the surrounding air-filled lung. (a) RPS short-axis view of the heart base showing the aorta (Ao) and main pulmonary artery (MPA). The operator should continue to obtain views more dorsally from this location (until imaging is no longer possible) in a search for a heart base mass. This dog had a pericardial effusion (PE) but no mass was identified. (b) LPS four-chamber view. It is important to obtain LPS views and optimize imaging for the heart base (in the far field). No mass was identified in this dog.

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7.143

Constrictive pericarditis will lead to a restrictive pattern of ventricular filling. This image shows mitral E and A waves from a cat with constrictive pericarditis, secondary to a foreign body and pyothorax. The E wave is markedly enlarged compared with the A wave. © 2008 British Small Animal Veterinary Association

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7.143 Constrictive pericarditis will lead to a restrictive pattern of ventricular filling. This image shows mitral E and A waves from a cat with constrictive pericarditis, secondary to a foreign body and pyothorax. The E wave is markedly enlarged compared with the A wave.

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7.144

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7.144 Necropsied canine heart with herniation and incarceration of the RV through a large pericardial defect. (Courtesy of J. Buchanan)

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7.145

(a) Lateral thoracic radiograph of a 13-year-old Lhasa Apso with an ovoid mass (*) arising from the cranial cardiac silhouette. This was a herniation of the RAu through a pericardial defect. (b) Jugular venography (digital subtraction fluoroscopy) demonstrates vascular contrast medium in the cranial vena cava (CrVC), entering the right atrium (RA) and the right ventricle (RV) and the herniated right auricular appendage (RAu). © 2008 British Small Animal Veterinary Association

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7.145 (a) Lateral thoracic radiograph of a 13-year-old Lhasa Apso with an ovoid mass (*) arising from the cranial cardiac silhouette. This was a herniation of the RAu through a pericardial defect. (b) Jugular venography (digital subtraction fluoroscopy) demonstrates vascular contrast medium in the cranial vena cava (CrVC), entering the right atrium (RA) and the right ventricle (RV) and the herniated right auricular appendage (RAu).

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7.146

Lateral radiograph of a dog with an iatrogenic pneumopericardium (arrowed) after surgery to repair a PPDH. Note that the air is constrained by the pericardial sac and that it outlines the major vessels, i.e. the actual heart is seen. © 2008 British Small Animal Veterinary Association

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7.146 Lateral radiograph of a dog with an iatrogenic pneumopericardium (arrowed) after surgery to repair a PPDH. Note that the air is constrained by the pericardial sac and that it outlines the major vessels, i.e. the actual heart is seen.

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7.148

RPS short-axis echocardiogram at the level of the heart base in a dog with a RAu haemangiosarcoma. The view has been optimized to best show the mass. The lesion is moderately cavitary (arrowed) and is outlined by pericardial effusion. RA = Right atrium. (Courtesy of B. Hopper) © 2008 British Small Animal Veterinary Association

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7.148 RPS short-axis echocardiogram at the level of the heart base in a dog with a RAu haemangiosarcoma. The view has been optimized to best show the mass. The lesion is moderately cavitary (arrowed) and is outlined by pericardial effusion. RA = Right atrium. (Courtesy of B. Hopper)

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7.149

RPS short-axis echocardiogram in a 9-year-old German Shepherd Dog at the level of the heart base. The view is optimized to show a RAu mass (arrowed). The mass is within the tip of the RAu and is outlined by pericardial effusion. CdVC = Caudal vena cava; RA = Right atrium. © 2008 British Small Animal Veterinary Association

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7.149 RPS short-axis echocardiogram in a 9-year-old German Shepherd Dog at the level of the heart base. The view is optimized to show a RAu mass (arrowed). The mass is within the tip of the RAu and is outlined by pericardial effusion. CdVC = Caudal vena cava; RA = Right atrium.

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7.150

(a) Right lateral and (b) DV views of an 11-year-old mixed breed dog with a heart base tumour. Note the focal cranial and right-sided deviation of the trachea at the heart base and cranial to the carina (arrowed). (c) RPS short-axis echocardiogram. There is a hypoechoic mass (M) lesion surrounding the ascending aorta (A). This was a heart base mass, most likely to be a chemodectoma, but no confirmation was obtained. © 2008 British Small Animal Veterinary Association

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7.150 (a) Right lateral and (b) DV views of an 11-year-old mixed breed dog with a heart base tumour. Note the focal cranial and right-sided deviation of the trachea at the heart base and cranial to the carina (arrowed). (c) RPS short-axis echocardiogram. There is a hypoechoic mass (M) lesion surrounding the ascending aorta (A). This was a heart base mass, most likely to be a chemodectoma, but no confirmation was obtained.

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7.151

(a) Right lateral radiograph and (b) transverse CT (post-contrast) image at the level of the mid-heart from a 10-year-old male neutered Cavalier King Charles Spaniel with a heart base mass. The CT image shows a heterogenously enhancing mass (M) wrapping around the aorta (A) and main pulmonary artery (MPA). (c) The dorsal reconstruction was of further use in defining the margins of the mass (M). © 2008 British Small Animal Veterinary Association

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7.151 (a) Right lateral radiograph and (b) transverse CT (post-contrast) image at the level of the mid-heart from a 10-year-old male neutered Cavalier King Charles Spaniel with a heart base mass. The CT image shows a heterogenously enhancing mass (M) wrapping around the aorta (A) and main pulmonary artery (MPA). (c) The dorsal reconstruction was of further use in defining the margins of the mass (M).

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7.152

LPS four-chamber view of a dog with a left atrial myxoma. A homogenous echoic mass is seen within the LA and part of the LAu (arrowed). LV = Left ventricle; RA = Right atrium; RV = Right ventricle. © 2008 British Small Animal Veterinary Association

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7.152 LPS four-chamber view of a dog with a left atrial myxoma. A homogenous echoic mass is seen within the LA and part of the LAu (arrowed). LV = Left ventricle; RA = Right atrium; RV = Right ventricle.

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7.153

(a) Lateral and (b) VD thoracic radiographs of a 12-year-old male Golden Retriever with heartworm disease. The pulmonary arteries are extremely enlarged and tortuous (arrowed). The cardiac silhouette is rounded and right-sided cardiomegaly is present. Incidental tiny metallic opacities represent lead shot from a previous injury. (c) DV thoracic radiograph of a 4-year-old Staffordshire Bull Terrier with heartworm disease. This radiograph was acquired 3 months after treatment for caval syndrome and heartworm disease but severe right-sided cardiac enlargement and main pulmonary artery enlargement (arrowed) are still evident. © 2008 British Small Animal Veterinary Association

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7.153 (a) Lateral and (b) VD thoracic radiographs of a 12-year-old male Golden Retriever with heartworm disease. The pulmonary arteries are extremely enlarged and tortuous (arrowed). The cardiac silhouette is rounded and right-sided cardiomegaly is present. Incidental tiny metallic opacities represent lead shot from a previous injury. (c) DV thoracic radiograph of a 4-year-old Staffordshire Bull Terrier with heartworm disease. This radiograph was acquired 3 months after treatment for caval syndrome and heartworm disease but severe right-sided cardiac enlargement and main pulmonary artery enlargement (arrowed) are still evident.

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7.154

VD view of a 7-year-old Domestic Medium-hair cat with heartworm disease, showing moderate to severe enlargement and lack of tapering of the caudal lobar pulmonary arteries (arrowed). © 2008 British Small Animal Veterinary Association

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7.154 VD view of a 7-year-old Domestic Medium-hair cat with heartworm disease, showing moderate to severe enlargement and lack of tapering of the caudal lobar pulmonary arteries (arrowed).

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7.155

Selective angiogram in a dog with chronic heartworm disease. Several catheters are present but the angiogram has been performed via a catheter in the main pulmonary artery. The contrast medium fills a markedly dilated main pulmonary artery and its branches. The caudal lobar pulmonary arteries are also tortuous and truncated. © 2008 British Small Animal Veterinary Association

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7.155 Selective angiogram in a dog with chronic heartworm disease. Several catheters are present but the angiogram has been performed via a catheter in the main pulmonary artery. The contrast medium fills a markedly dilated main pulmonary artery and its branches. The caudal lobar pulmonary arteries are also tortuous and truncated.

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7.156

(a) RPS short-axis ultrasound image of the heart base and pulmonary arteries of a 7-year-old male neutered mixed breed dog. Several adult worms are identified in the right pulmonary artery (arrowed). (b) LPS long-axis four-chamber echocardiogram of a 4-year-old Staffordshire Bull Terrier with caval syndrome due to heartworm disease. A large mass of adult heartworms (H) is present in an enlarged RA. They are identified as parallel echogenic lines. (c) RPS short-axis echocardiogram obtained at the level of the papillary muscles in the same dog as (b). During diastole the worms were seen to move through the tricuspid valve and into the enlarged RV. HW = Heartworm mass; LV = Left ventricle; RV = Right ventricle. © 2008 British Small Animal Veterinary Association

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7.156 (a) RPS short-axis ultrasound image of the heart base and pulmonary arteries of a 7-year-old male neutered mixed breed dog. Several adult worms are identified in the right pulmonary artery (arrowed). (b) LPS long-axis four-chamber echocardiogram of a 4-year-old Staffordshire Bull Terrier with caval syndrome due to heartworm disease. A large mass of adult heartworms (H) is present in an enlarged RA. They are identified as parallel echogenic lines. (c) RPS short-axis echocardiogram obtained at the level of the papillary muscles in the same dog as (b). During diastole the worms were seen to move through the tricuspid valve and into the enlarged RV. HW = Heartworm mass; LV = Left ventricle; RV = Right ventricle.

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7.157

(a) RPS long-axis echocardiogram of the same dog as in Figure 7.156b after heartworm removal. Note the enlarged right atrium (RA) and compare its size to that of the left atrium (LA). (b) RPS short-axis echocardiogram obtained at the heart base and optimized for the main pulmonary artery (MPA). The main pulmonary artery is enlarged both before and after the pulmonic valve. Usually, the main pulmonary artery is close to the diameter of the aorta (Ao) at this level. (c) M-mode echocardiogram obtained at the level of the papillary muscles from a RPS location. The right ventricle (RV) is markedly dilated. The left ventricle (LV) is also marked for comparison. © 2008 British Small Animal Veterinary Association

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7.157 (a) RPS long-axis echocardiogram of the same dog as in Figure 7.156b after heartworm removal. Note the enlarged right atrium (RA) and compare its size to that of the left atrium (LA). (b) RPS short-axis echocardiogram obtained at the heart base and optimized for the main pulmonary artery (MPA). The main pulmonary artery is enlarged both before and after the pulmonic valve. Usually, the main pulmonary artery is close to the diameter of the aorta (Ao) at this level. (c) M-mode echocardiogram obtained at the level of the papillary muscles from a RPS location. The right ventricle (RV) is markedly dilated. The left ventricle (LV) is also marked for comparison.

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7.158

(a) Right lateral thoracic radiograph of a 6-year-old spayed Golden Retriever bitch with angiostrongylosis, showing a patchy, peripheral alveolar pattern. A pleural fissure line can also be seen. (b) Right lateral thoracic radiograph of a 5-year-old Cocker Spaniel with angiostrongylosis. The peripheral alveolar pattern is more severe in this case. (c) Thoracic ultrasound image from the same dog as in (b) obtained with a linear transducer via an intercostal approach. A peripheral hypoechoic consolidated region of lung (*) is identified. Ultrasound-guided aspiration of this region confirmed the diagnosis of angiostrongylosis. © 2008 British Small Animal Veterinary Association

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7.158 (a) Right lateral thoracic radiograph of a 6-year-old spayed Golden Retriever bitch with angiostrongylosis, showing a patchy, peripheral alveolar pattern. A pleural fissure line can also be seen. (b) Right lateral thoracic radiograph of a 5-year-old Cocker Spaniel with angiostrongylosis. The peripheral alveolar pattern is more severe in this case. (c) Thoracic ultrasound image from the same dog as in (b) obtained with a linear transducer via an intercostal approach. A peripheral hypoechoic consolidated region of lung (*) is identified. Ultrasound-guided aspiration of this region confirmed the diagnosis of angiostrongylosis.

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7.159

(a) Pre-contrast high-resolution CT image of the lung of a 9-year-old Rottweiler with PTE at the level of the accessory lung lobe. Note the wedge-shaped peripheral pulmonary consolidation (straight black arrow) and distended lobar artery (anti-clockwise white bent arrow) of the left caudal lung lobe, the diminished size of the right caudal lung lobe lobar artery (clockwise bent arrow), and both left and right caudal lung lobe lobar veins (arrowheads). Left of dog is right side of image. (b) Post-contrast CT angiography image at the level of the main pulmonary artery. Notice the large contrast medium filling defect in the main pulmonary artery (bent arrow) and left pulmonary artery (arrowhead). This large thrombus extended caudally, distending the diameter of the main pulmonary artery and resulting in peripheral oligaemia. Ao = Aorta (seen as two circles as both the aortic arch and descending aorta are seen in cross section at this level). © 2008 British Small Animal Veterinary Association

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7.159 (a) Pre-contrast high-resolution CT image of the lung of a 9-year-old Rottweiler with PTE at the level of the accessory lung lobe. Note the wedge-shaped peripheral pulmonary consolidation (straight black arrow) and distended lobar artery (anti-clockwise white bent arrow) of the left caudal lung lobe, the diminished size of the right caudal lung lobe lobar artery (clockwise bent arrow), and both left and right caudal lung lobe lobar veins (arrowheads). Left of dog is right side of image. (b) Post-contrast CT angiography image at the level of the main pulmonary artery. Notice the large contrast medium filling defect in the main pulmonary artery (bent arrow) and left pulmonary artery (arrowhead). This large thrombus extended caudally, distending the diameter of the main pulmonary artery and resulting in peripheral oligaemia. Ao = Aorta (seen as two circles as both the aortic arch and descending aorta are seen in cross section at this level).

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7.160

Dorsal static image of the lungs in a middle-aged, mixed breed dog with Cushing’s disease presented for evaluation of possible PTE. The image was obtained 10 minutes after intravenous injection of 99mTc MAA. Thoracic radiographs obtained immediately prior to scintigraphy were unremarkable. Note the large wedge-shaped photopenic area, which occupies the majority of the right caudal lung lobe, consistent with a large lobar pulmonary embolus. © 2008 British Small Animal Veterinary Association

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7.160 Dorsal static image of the lungs in a middle-aged, mixed breed dog with Cushing’s disease presented for evaluation of possible PTE. The image was obtained 10 minutes after intravenous injection of 99mTc MAA. Thoracic radiographs obtained immediately prior to scintigraphy were unremarkable. Note the large wedge-shaped photopenic area, which occupies the majority of the right caudal lung lobe, consistent with a large lobar pulmonary embolus.

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7.161

Ventral (left of image) and dorsal (right of image) static images of the lungs obtained 5 minutes after intravenous injection of 99mTc-MAA in a 4-year-old Beagle with heartworm disease. Thoracic radiographs obtained immediately prior to scintigraphy showed no focal pulmonary parenchymal abnormalities. Notice the complete lack of blood flow to the right cranial, caudal and accessory lobes, with minimal perfusion to the right middle lobe (arrowed). There is also a pleural based, wedge-shaped defect along the diaphragmatic border of the left caudal lobe, best seen in the ventral view. © 2008 British Small Animal Veterinary Association

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7.161 Ventral (left of image) and dorsal (right of image) static images of the lungs obtained 5 minutes after intravenous injection of 99mTc-MAA in a 4-year-old Beagle with heartworm disease. Thoracic radiographs obtained immediately prior to scintigraphy showed no focal pulmonary parenchymal abnormalities. Notice the complete lack of blood flow to the right cranial, caudal and accessory lobes, with minimal perfusion to the right middle lobe (arrowed). There is also a pleural based, wedge-shaped defect along the diaphragmatic border of the left caudal lobe, best seen in the ventral view.

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7.162

(a) Post-contrast transverse CT scan (soft tissue algorithm and window) of a 6-year-old male neutered Labrador Retriever with a Budd–Chiari-like syndrome due to a CdVC mass. The image was obtained caudal to the heart. The mass (M) is seen as a large soft tissue attenuating structure with a small amount of contrast medium within the CdVC ventral to it. There is also atelectasis of the ventral tip of the right caudal lung lobe. (b) A more caudal image from the same CT series. The caudal part of the mass (M) has large regions of mineralization (these were also hyperdense pre-contrast administration). The peritoneal effusion (E) is evident on this image, surrounding the liver lobes (L). © 2008 British Small Animal Veterinary Association

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7.162 (a) Post-contrast transverse CT scan (soft tissue algorithm and window) of a 6-year-old male neutered Labrador Retriever with a Budd–Chiari-like syndrome due to a CdVC mass. The image was obtained caudal to the heart. The mass (M) is seen as a large soft tissue attenuating structure with a small amount of contrast medium within the CdVC ventral to it. There is also atelectasis of the ventral tip of the right caudal lung lobe. (b) A more caudal image from the same CT series. The caudal part of the mass (M) has large regions of mineralization (these were also hyperdense pre-contrast administration). The peritoneal effusion (E) is evident on this image, surrounding the liver lobes (L).

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7.163

Lateral view of an 11-year-old spayed Labrador Retriever bitch with recurrence of severe oedema of the head, neck and forelimbs 1 week after removal of a thymoma. Non-selective angiography via the cephalic vein demonstrated a large intraluminal filling defect (arrowed) consistent with a thrombus in the CrVC at the level of the costocervical vein. A repeat angiogram 2 weeks later showed the thrombus to be approximately half the size. (Courtesy of D. Davies) © 2008 British Small Animal Veterinary Association

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7.163 Lateral view of an 11-year-old spayed Labrador Retriever bitch with recurrence of severe oedema of the head, neck and forelimbs 1 week after removal of a thymoma. Non-selective angiography via the cephalic vein demonstrated a large intraluminal filling defect (arrowed) consistent with a thrombus in the CrVC at the level of the costocervical vein. A repeat angiogram 2 weeks later showed the thrombus to be approximately half the size. (Courtesy of D. Davies)

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7.164

A selective coronary angiogram with the contrast medium injection made just beyond the level of the aortic valve in a normal dog. This dog has the normal arrangement of left and right coronary arteries. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.164 A selective coronary angiogram with the contrast medium injection made just beyond the level of the aortic valve in a normal dog. This dog has the normal arrangement of left and right coronary arteries. (Courtesy of J. Buchanan)

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7.165

A selective coronary angiogram in a 5-month-old Bulldog bitch puppy. A single right coronary artery is present and resulted in pulmonic stenosis. (Courtesy of J. Buchanan) © 2008 British Small Animal Veterinary Association

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7.165 A selective coronary angiogram in a 5-month-old Bulldog bitch puppy. A single right coronary artery is present and resulted in pulmonic stenosis. (Courtesy of J. Buchanan)

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7.166

Postmortem radiograph from a dog with mineralized coronary arteries due to atherosclerosis. The dog also had hypothyroidism, which has been strongly linked with this condition. © 2008 British Small Animal Veterinary Association

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7.166 Postmortem radiograph from a dog with mineralized coronary arteries due to atherosclerosis. The dog also had hypothyroidism, which has been strongly linked with this condition.