Hypertrophic Cardiomyopathy in Cats

Hypertrophic Cardiomyopathy in Cats

Hypertrophic Cardiomyopathy is a primary myocardial disease wherein the heart muscle is damaged.

The myocytes (muscle cells) become markedly thickened and replicate in a non-uniform pattern.

This causes the ventricle (pumping chamber) to become severely thickened, which reduces the chamber size for blood.  

This disease is characterized by a diastolic (filling) failure.  

This causes the left atrium to dilate as it is unable to push the blood into the small left ventricular chamber.  

This eventually can lead to the development of congestive heart failure (fluid in the lungs), which is a medical emergency that makes breathing very difficult.  

This disease is typically progressive; however, the rate of progression is highly variable.  

Recheck echocardiograms are necessary to monitor the rate of change, chamber sizes, and determine if any medications or adjustments are indicated.

Once the left atrium has dilated, affected patients are at an increased risk for thromboembolic disease.  

This is when a blood clot forms within the left atrium or auricle, which can dislodge and go to various points within the body.  

The most common location is the distal aorta (often termed a “saddle thrombus”), which supplies the rear limbs with blood.  

When this happens, affected patients are very painful, the limbs cool to touch, and the legs are typically non-functional.  

The right front leg is the second most common location.  Any other clinical signs are determined by the site of the clot lodging.  This could include sudden death if the brain were to be affected by this.  

Anti-platelet medications are utilized to minimize the chances of this developing; however, no medications are 100% effective in preventing this condition.

Plavix has been recently shown by the FAT CAT study to be the most effective antiplatelet medication in our feline friends.  

If you notice any clinical signs or leg weakness, consider it a medical emergency.