Hypertrophic Cardiomyopathy in Cats
Dilated cardiomyopathy occurs when the heart muscle loses its tone and becomes flaccid. The heart chambers overfill, the walls of the ventricles become thinner, and the chambers enlarge. One cause of dilated cardiomyopathy is taurine deficiency. Taurine is an essential amino acid present in high concentrations in animal tissue. Feeding dog food or a grain-based cat food could lead to taurine deficiency. Most commercial cat foods are currently supplemented with taurine. Dog foods are not, so a cat eating dog food has a high risk of developing dilated cardiomyopathy.
Another cause of dilated cardiomyopathy is myocarditis, which is inflammation of the heart muscle. Viruses and autoimmune diseases have been implicated as the cause of myocarditis in humans, although its cause is unknown in cats.
Dilated cardiomyopathy is often a rapid-onset disease that progresses over two or three days as the heart begins to fail. The most frequent sign is labored breathing at rest. The cat often sits with his head and neck extended and elbows out, straining to take in air. Cool feet and ears and a body temperature below normal are signs of poor circulation. Heart murmurs are common. The pulse is often rapid and thready and may be irregular or even slow. Loss of appetite, rapid weight loss, weakness, fainting attacks, and crying out spells often accompany the signs. A clot blocking the vascular pathway to the rear legs may be the first sign. Echocardiography is the best method for diagnosing dilated cardiomyopathy.
Treatment: Treatment of dilated cardiomyopathy is directed at correcting any taurine deficiency and controlling fluid retention. Fluid retention is best managed using diuretics such as furosemide (Lasix). Cats with taurine deficiency cardiomyopathy who survive the first week of supplementation have an increased chance for survival, but it can take four to six months for the heart muscle to heal.