
09/24/2025
Hypertrophic Cardiomyopathy in Cats 🐾🫀
HCM is the most common heart disease in cats. It causes the heart muscle to become abnormally thickened, which makes it harder for the heart to fill with blood — a condition known as diastolic failure.
As the heart struggles to fill, pressure builds and the left atrium enlarges, which can lead to:
Congestive heart failure (fluid in the lungs)
Labored breathing — a life-threatening emergency
📈 HCM is progressive, but the speed of progression varies between cats. Routine echocardiograms are essential to track changes and adjust treatment.
⚠️ An enlarged left atrium increases the risk for thromboembolic events — blood clots that can travel through the body. The most common is a "saddle thrombus", where a clot blocks blood flow to the hind legs, causing:
-Sudden pain
-Cold, non-functional limbs
-Distress or paralysis
💊 The FAT CAT study found Plavix (clopidogrel) to be the most effective antiplatelet medication to reduce clot risk in cats, but we do have several preventative options available!
🚨 Sudden limb weakness, pain, or difficulty breathing? Get to a vet immediately. Time matters.