Case Studies In Small Animal

Cardiovascular Medicine

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Case 5

Pathology

There was no evidence of pleural effusion or pulmonary edema on post mortem examination, confirming that Alice did not die of heart failure and so most likely died suddenly.

Alice's heart weighed 31 grams. The normal heart weight for an adult cat should be less than 20 grams. Cats with severe hypertrophic cardiomyopathy have a heart weight greater than 30 grams. The worst heart from a cat with severe HCM that I have seen weighed 38 grams.

The image above is taken from the front of the unopened heart. The left auricle is at the top on the right and the right auricle is to the left. Note that the left auricle is enlarged when compared to the right auricle.

This is a cross-sectional view primarily of the left ventricle. The heart has undergone rigor (contracture) post mortem and so the lumen of the left ventricle and the wall thicknesses are more comparable to a systolic frame on an echocardiogram than a diastolic frame. Note that the left ventricular cavity is almost obliterated (end-systolic cavity obliteration). Also note the extremely enlarged papillary muscles in the cross-sectional view on the right.

This is a longitudinal section through the left atrium, mitral valve, and aorta. The arrow points to the narrowed left ventricular outflow tract, between the basilar region of the interventricular septum (where the arrow lies) and the anterior leaflet of the mitral valve. The outflow tract leads out into the aorta. The enlarged left atrium lies above the mitral valve.

Mark D. Kittleson, D.V.M., Ph.D. All rights reserved.