Hypertrophic Cardiomyopathy (HCM) is one of the most common heart diseases in cats and is the most common cause of sudden death in indoor cats. Essentially it is an abnormal thickening of one or several areas of the walls of the heart, usually the left ventricle.
The disease is caused by a variety of genetic abnormalities of the cardiac muscle proteins that are prevalent in Ragdolls, Main Coons, Oriental Breeds and Devon Rex’s, but also common in domesticated short hair cats.
The disease is usually diagnosed at middle-age but there’s also a juvenile form that affects young cats (usually Ragdolls).
There are many different forms of hypertrophy which means the impact of the thickening of the walls of the heart is variable. In mild cases, cats can remain symptom free for their whole life however, in severe cases, the ventricle will have a hard time distending which leads to increased intra-cardiac pressure and congestive heart failure.
Other complications of the disease include cardiac arrhythmias, leading to fainting or sudden death and clot formation in the left atrium. These clots may fragment and travel in the aorta and obstruct a major artery.
Symptoms range in severity from difficult breathing, to extreme lethargy, collapsing and even sudden death.
To diagnose HCM, your cat will likely need x-rays, electrocardiograms (ECG), blood work or blood pressure monitoring.
Treatment can involve hospitalisation to treat congestive heart failure which results in abnormal fluid accumulation in the lungs. Treatment typically includes oxygen therapy, diuretics, blood pressure monitoring, and medications to make the heartbeat more efficiently.
The aim of treatment is to slow the heart rate, correct abnormal heart beats, improve blood flow, decrease blood clot formation and alleviate fluid build-up.
