In "Feline cardiology: A review of the basics," at the 2014 American College of Veterinary Internal Medicine Forum, Jan Bright, DVM, MS, DACVIM (internal medicine, cardiology), discussed some of the peculiarities of feline cardiology and offered tips to keep in mind when evaluating feline patients with suspected heart disease.
GETTY IMAGES/JOEL SARTORE
The first thing Dr. Bright pointed out is that, unlike in dogs, cats with heart disease rarely present for coughing, which is more often a clinical sign of an underlying respiratory disorder. Also, unlike the insidious onset of signs in dogs with heart disease, cats are more likely to present acutely and with advanced disease.
During the physical examination, Dr. Bright recommended using a pediatric stethoscope for auscultation in cats given their small heart size. The bell of a pediatric scope will also be the most sensitive in detecting the presence of a gallop rhythm. She also pointed out that cats with congestive heart failure (CHF) may not always have audible crackles and that massive ascites is rare in cats with CHF. Pleural effusion in cats may also be noted with left-sided heart failure with or without pulmonary edema.
When evaluating thoracic radiography in cats with suspected cardiac disease, Dr. Bright offered these tips:
> In cats, left atrial enlargement may not cause a loss of the caudal cardiac waist as seen in dogs.
> The main pulmonary artery in cats is along the midline, so cardiac enlargement may not cause a bulge in the 1- or 2-o'clock position in the ventrodorsal view as seen in dogs.
> A normal vertebral heart score in cats is 7.5 to 8. A score > 8 is supportive of cardiomegaly, although exact chamber enlargement may be difficult to discern from radiographs alone.
> As cats age, the axis of the heart may appear more horizontal in the lateral view and the ascending aorta (aortic root) may appear larger. However, an enlarged aortic root may be indicative of systemic hypertension and should be evaluated.
> A valentine-shaped heart does not always mean biatrial enlargement—only the left atrium may be enlarged.
> Pulmonary edema may develop in atypical patterns.
Echocardiography will be needed to assess the exact nature of the underlying cardiac disease and to determine the best course of long-term therapy.