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13

Acquired Heart Disease
Merrilee Holland

Department of Clinical Sciences, College of Veterinary Medicine, Auburn, AL, USA

13.1 Thoracic Radiographs to the cardiac silhouette so as not to miss enlargement at
for Cardiovascular Disease this site, which can be seen with pulmonary hypertension.
The pulmonary parenchyma in cats in cardiovascular
The shape and size of the cardiac silhouette need to be crit­ failure has a more random distribution than in dogs. Patchy
ically evaluated for evidence of enlargement. Mild round­ interstitial to alveolar opacity has been documented in
ing of the left ventricular border noted on the lateral image patients with pulmonary edema. In cats with cardiomyopa­
can be the earliest radiographic evidence of many forms of thy, pleural effusion may be seen with left‐sided heart
cardiac disease. On the ventrodorsal image, the apex of the failure.
heart typically lies in the left hemithorax, but an enlarged
left ventricle can be displaced into the right hemithorax as
well. The left atrium is located at the 1–2 o’clock position 13.2 Echocardiograms
on the ventrodorsal image. On the lateral image, displace­
ment and compression of the caudal mainstem bronchi It is important to remember that cardiovascular disease
due to left atrial enlargement are not as evident as seen in in feline patients is not limited to cardiomyopathies.
canine patients. Left atrial enlargement primarily forms Evaluation on the 2D image of the left atrial size, interven­
the basis of the “valentine” shape on the ventrodorsal tricular septum, and left ventricular free wall thickness in
image according to a study comparing left and right atrial systole and diastole, and the left and right ventricular
size on radiographs and echocardiograms in 81 cats. The chamber size is essential in interpretation of cardiac dis­
right atrial size provides significant contribution to the ease. The left atrial size when measured from the right par­
heart base width only when severe left atrial enlargement asternal short axis view should not be greater than 1.5 cm
is present (Figure 13.1) [1]. [2]. When the left atrium is measured from the right par­
The size and shape of the aorta should be evaluated for asternal longitudinal axis view, the size should be less than
evidence of systemic hypertension. The undulating appear­ 1.57 cm (Figure 13.4) [3]. The interventricular septum and
ance or uncoiling of the aorta has been documented with left ventricular free wall should be measured from an M‐
systemic hypertension (Figure 13.2). When the size of the mode tracing from a right parasternal short axis view.
ascending aorta surpasses the size of the descending aorta These wall measurements in diastole should not be greater
as it nears the diaphragm, systemic hypertension should be than 0.6 cm. As a rule of thumb, the left ventricular cham­
suspected (Figure 13.3). All four sets of pulmonary vessels ber in diastole should be 1.5 cm and in systole 0.9 cm when
need to be evaluated each time. Unfortunately, not all sets measured from M‐mode. Supplemental measurements of
of vessels will appear altered with cardiovascular disease. the interventricular septum or left ventricular free wall aid
The cranial lobar vessels, artery, and vein should be similar in diagnosis of hypertrophy but should not replace M‐mode
in size and are best evaluated on the lateral projection. The tracing measurements. M‐mode of the mitral valve (E‐
caudal lobar vessels, artery, and vein should be similar in point septal separation) from a right parasternal long axis
size and not as large as the width of the ninth rib. It is view typically should be less than 0.2 cm. Systolic anterior
important to follow the pulmonary arteries passing dorsal motion or movement of typically the septal leaflet of the

Feline Diagnostic Imaging, First Edition. Edited by Merrilee Holland and Judith Hudson.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.