Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Two The Thorax 159
A
B
Fig. 2-135 An 11-year-old neutered male domestic short-haired cat with anorexia and lethargy. A
grade 3/6 murmur was auscultated. A, A right parasternal short-axis view of the left ventricle reveals
both left (lv) and right ventricular (rv) dilation. B, An M-mode view through the left ventricle reveals
marked right (rv) and left (lv) ventricular dilation. Minimal change in the ventricular diameter is
present between systole and diastole. Diagnosis: Dilated cardiomyopathy.
Fig. 2-136 An 11-year-old Golden
Retriever had exercise intolerance
and peripheral lymphadenopathy.
The two-dimensional echocardiogram
reveals a moderate to large volume
of pericardial effusion (PE).
The myocardium (right ventricular
free wall [RVFW], interventricular
septum [IVS], and left ventricular
free wall [LVFW]) is markedly thickened
and heteroechoic. Diagnosis:
Infiltrative cardiomyopathy (lymphoma).
Hypertrophic Cardiomyopathy. There are no survey radiographic findings that can be
used to differentiate unequivocally dilated and hypertrophic cardiomyopathy (Fig. 2-
137). The cardiac silhouette alterations are similar in all types of feline cardiomyopathy.
The valentine shape on the ventrodorsal view is more common in hypertrophic cardiomyopathy.
The cardiac silhouette may even appear to be normal. More commonly, the
cardiac silhouette will enlarge, particularly the atrial areas in moderate or severe
cases. 401,402,409
Echocardiographic changes include hypertrophy of the left ventricular myocardium
(including free wall, septum, or both), dilation of the left atrium, decreased ventricular
luminal diameter, and normal to increased fractional shortening (Fig. 2-138). Particular
attention should be paid to the motion of the septal leaflet of the mitral valve. In some cases
it may open during ventricular systole, causing a dynamic partial obstruction to the aortic
outflow tract. This is referred to as systolic anterior motion of the mitral valve.
Occasionally the ventricle will be dilated and have ventricular hypertrophy. On rare occasions,
a thrombus may be identified in the left atrium or ventricle (Fig. 2-139). 410