Myocardial infarction in dogs and cats: 37 cases (1985-1994).

OBJECTIVE

To determine the incidence of acute and subacute myocardial infarction on postmortem examination, identify associated diseases, and evaluate clinical or diagnostic indicators of myocardial infarction in dogs and cats.

DESIGN

Retrospective study.

ANIMALS

32 dogs and 5 cats.

PROCEDURE

Records from the necropsy service from December 1985 through August 1994 were searched for dogs and cats in which acute or subacute myocardial infarction was diagnosed on postmortem examination. Clinical records were reviewed for signalment, initial owner complaint, medical history, results of physical examination, electrocardiography, radiography, echocardiography, CBC, serum chemistry analysis, urinalysis, and coagulation profile as well as clinical course, outcome, necropsy findings, and results of histologic evaluation.

RESULTS

Initial owner complaints and physical examination findings were consistent with associated diseases. Electrocardiographic abnormalities in dogs included ventricular tachycardia (16%), atrial fibrillation (9%), and premature ventricular contractions (6.5%). Premature ventricular contractions were noticed in 2 cats. Echocardiography revealed dilated, poorly contractile hearts (n = 3) and thickened mitral valves (2) in dogs, and ventricular hypertrophy (3) in cats. Ninety-seven percent of dogs had infarction of the left ventricle as well as other other portions of the heart. Infarctions in cats were found in all parts of the myocardium including the right ventricle (n = 3), left ventricle (3), and interventricular septum (1).

CLINICAL IMPLICATIONS

Myocardial infarction is rare in dogs and cats. It is associated with a number of common diseases and may contribute to morbidity and mortality in those dogs and cats that are critically ill.