Objective—To assess the frequency of heart murmurs
in overtly healthy cats.
Sample Population—103 healthy domestic cats.
Procedure—Background information and physical
characteristics were assessed in cats that were candidates
for blood donation during an 8-month period. For
cats with heart murmurs, additional information collected
included murmur timing, grade, point of maximal
intensity, and presence of additional heart sounds.
Results—Heart murmurs were detected in 22 of the
103 (21%) cats. Echocardiography was performed in 7
of those 22 cats. The echocardiogram was considered
normal in 1 cat; in the other 6 cats, diagnoses included
hypertrophic cardiomyopathy (interventricular septal
hypertrophic form [IVSH]; n = 4), left ventricular
concentric hypertrophy with valvular disease (1), and
equivocal IVSH (1). Thirteen cats had more than 1
examination during the study; 3 of them developed
heart murmurs. There were no significant differences
in age, sex, breed, coat color, eye color, or heart rate
between cats with and without murmurs. Among the
103 cats, there were 6 pairs of siblings from 6 multiple-
cat households and 16 cats from 7 multiple-cat
households in which the cats were not related; the
proportion of cats with murmurs was higher in the
related cats (5/12) than in the unrelated cats (3/16),
but the difference was not significant.
Conclusions and Clinical Relevance—Results indicated
that heart murmurs are detectable in a large
proportion of overtly healthy cats and that many murmurs
appear to be caused by structural heart disease
that is in a clinically latent state. ( J Am Vet Med Assoc 2004;225:384–388)