Cat Diseases - Feline Hypertrophic Cardiomyopathy

feline infectious peritonitis
  • This is the most common cause of heart disease in cats and the most frequent cause of spontaneous death in indoor adult cats.
  • In cats with this condition, the walls of the ventricles become thick.
  • The muscle fibers are replaced by fibrous connective tissue (scar tissue), results in poor relaxing and filling ability. In fact, the heart is actually weakened as the affected wall of the heart becomes less elastic and the heart chambers get smaller.
  • As a result less blood can enter the chamber; thus, less blood is ejected out to the body.
  • In addition, blood clots may develop in the left atrium. If a clot breaks up, small pieces of it may circulate and eventually lodge in an artery leading to the legs. This may cause the sudden onset of lameness or paralysis, often accompanied by severe pain.
  • The cause for hypertrophic cardiomyopathy may remain unknown in many cases. However, genetic mutations and predispositions are known to lead to HCM in cats.
  • Hypertrophic cardiomyopathy tends to affect cats one to five years of age, and male cats are more commonly affected.
  • HCM is often associated with Hyperthyroidism and/or hypertension in cats.
  • Maine Coons and American Shorthairs have a predisposition towards HCM.
    A cat with hypertrophic cardiomyopathy may display no symptoms at all, but die suddenly and unexpectedly. Symptoms may include.
    • Loss of appetite (anorexia)
    • Lethargy
    • Weak pulse
    • Difficulty breathing
    • Decreased activity
    • Short, rough, snapping breathing sounds (crackles)
    • Inability to tolerate exercise or exertion
    • Bluish discoloration of foot pads and nailbeds (indicates a lack of oxygen flow to the legs)
    • Collapse
    • Sudden heart failure
    • Irregular heart rhythm
    • Heart murmur
    • Gagging
    • Lameness or paralysis of the hind legs
Feline infectious peritonitis
  • Your cat will be hospitalized for appropriate care, especially if it is suffering from congestive heart failure.
  • Your cat will be placed in a quiet environment to minimize stress, and if it is having trouble breathing it will be given oxygen therapy.
  • There are several possible medications that can be used to treat hypertrophic cardiomyopathy:
        Diuretics if congestive heart failure is present.
        Beta-blockers to reduce the heart rate if it is excessive.
        Calcium channel-blockers to help the heart muscle relax and hence help more effective filling of the heart.
        Aspirin to decrease risk of blood clots
        Warfarin to prevent blood clotting
        Angiotensin Converting Enzyme (ACE) inhibitors - these drugs also help to control congestive heart failure.
        Drugs to lower blood pressure - additional medications may be needed to treat hypertension.
  • The cat should be put on a sodium-restricted diet, especially if there is congestive heart failure, to keep the pressure in the blood stable.
  • Providing a quiet and safe space for your cat, away from other pets and active children, is important to its recovery.