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.

Photograph of Alice's unopened heart viewed from the front. The left auricle is at the top right and the right auricle is to the left. The left auricle is visibly enlarged compared to the right auricle.
Unopened heart viewed from the front. The left auricle (top right) is enlarged compared to the right auricle (left).
Cross-sectional view primarily of the left ventricle in rigor (post-mortem contracture). The left ventricular cavity is almost obliterated (end-systolic cavity obliteration). The papillary muscles in the cross-section on the right are extremely enlarged.
Cross-sectional view of the left ventricle. The heart is in rigor (post-mortem contracture), so wall thicknesses are comparable to a systolic echocardiographic frame. Note the near-obliteration of the LV cavity and the extremely enlarged papillary muscles.
Longitudinal section through the left atrium, mitral valve, and aorta. An arrow points to the narrowed left ventricular outflow tract between the basilar region of the interventricular septum and the anterior leaflet of the mitral valve. The outflow tract leads into the aorta. The enlarged left atrium lies above the mitral valve.
Longitudinal section through the left atrium, mitral valve, and aorta. The arrow points to the narrowed left ventricular outflow tract (LVOT) between the basilar interventricular septum and the anterior mitral valve leaflet. The enlarged left atrium lies above the mitral valve.
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