Hypertrophic Cardiomyopathy (HCM)

Hypertrophic Cardiomyopathy (HCM)

Species: Cat

Breeds Affected: All breeds (heritable in some, eg, Maine Coon and Ragdoll)

The most common heart disease in cats, characterized by thickening of the left ventricular muscle wall. This reduces chamber volume and impairs the heart’s pumping ability, potentially leading to congestive heart failure, arrhythmias, or thromboembolic events.

• Early stages may be asymptomatic; later
• signs include labored or rapid breathing
• panting (especially after exertion)
• lethargy
• hiding
• poor appetite
• and in some cases
• hind limb paralysis (saddle thrombus) or sudden collapse.

There is no cure, so management focuses on reducing complications. Diuretics are used if congestive heart failure is present, beta-blockers to slow heart rate, and ACE inhibitors to reduce cardiac workload. Lifestyle modifications to reduce stress are also recommended.

Furosemide (diuretic) to relieve fluid buildup; atenolol (beta-blocker) to slow the heart rate; clopidogrel to reduce clot risk; ACE inhibitors (benazepril or enalapril); sometimes spironolactone; and in some cases, pimobendan (although not routinely used).