Cardiomyopathy in cats

Written by Liz Palika Reviewed by Kristin Westafer, DVM

Overview

Feline cardiomyopathy literally means 'disease of the heart muscle of a cat'. There are three forms of cardiomyopathy appreciated in feline medicine: hypertrophic, dilated, and restrictive. In hypertrophic cardiomyopathy the muscle of the major chambers of the heart thicken and decrease the amount of blood that can be pumped with every heartbeat. In the dilated form of cardiomyopathy, the heart walls stretch and the heart cannot contract properly to move blood throughout the body. In restrictive cardiomyopathy, the heart does not function properly and may be thickened in some areas; usually the heart does not contract properly. Without veterinary intervention and care, these forms can be very serious and potentially fatal.

Symptoms

Symptoms for the types of cardiomyopathy can creep up very subtly as cats tend to hide physical problems. However, eventually the owner will see:

A lessening of physical activity (hard to appreciate in our sedentary cats)
Poor appetite
Unexplained weight loss
Panting
Fainting
Coughing
Increased respiratory rate
Increased respiratory effort
Cool limbs and paw pads

As the cardiomyopathy continues and the heart is increasingly stressed, the symptoms get worse:

Extreme inactivity
Labored breathing
Increased respiratory rate

Cause and prevention

Dilated cardiomyopathy can be caused by a deficiency of the amino acid taurine. Commercial cat foods today contain a taurine supplement for this specific reason; however, if the owner is feeding the cat a home made diet and is not adding an appropriate taurine supplement, then dilated cardiomyopathy can result. The number of cases of dilated cardiomyopathy has decreased significantly since the late 1980’s and is rarely seen today in cats.

There is a genetic predisposition towards hypertrophic cardiomyopathy in some breeds of cats, specifically the Maine Coon and Ragdoll breeds. However, any breed of cat can be affected. With these cats, the age of onset is usually between one and four years, and the disease seems to affect males more severely than females. A genetic test is available for the Maine Coon and Ragdoll breeds to test for the gene responsible for hypertrophic cardiomyopathy and responsible breeders should be testing their breeding stock. Cats with the disease should be removed from any breeding program.

Restrictive cardiomyopathy typically affects middle aged or older females. This disease may be more common in certain purebred cats, like the Persian, Birman, Balinese, Siamese, and Burmese breeds. The cause for this form of cardiomyopathy is likely genetic

In addition to genetics, hyperthyroidism can cause hypertrophic cardiomyopathy, as can an inflammation of the heart muscles. Toxins, viruses, bacteria, and protozoal infections can all damage the heart. Unfortunately, in many instances the cause of the cardiomyopathy is unknown.

Treatment

The initial examination and tests for cardiomyopathy will include a check to see if any underlying health problems may have led to the heart disease. These problems, such as an inflammation or thyroid disease, will be treated and the heart may become normal again in the future.

Many different types of medications can help control the cardiomyopathy, depending upon the severity of the disease. Some medications, if given over a long period of time can help reverse the changes of hypertrophic cardiomyopathy. One danger to the cat is the tendency for cats with cardiomyopathy to develop blood clots, which can be life threatening. Low doses of aspirin can be given in hopes of preventing this from happening. In addition, all types of cardiomyopathy can, even with treatment, can lead to heart failure. If heart failure occurs, your cat will likely need hospitalization for oxygen therapy, medications, and removal of fluid from the chest to help them breathe easier. Cats in heart failure often accumulate fluid around their lungs and they have difficulty breathing; if the heart failure can be controlled with medications, the amount of fluid that accumulates in the chest will likely decrease over time.

The costs of diagnosing and treating cardiomyopathy will vary, from $20 to $50 for the initial examination, to $300 to $600 or more for additional tests. An echocardiogram should be performed if cardiomyopathy is suspected in your pet; this may require referral to a veterinarian that is specifically trained to use this equipment. Medications will also vary in cost; from pennies for a baby aspirin to several dollars a day for more serious cases. Medications will be required for the rest of your cat’s life if they are diagnosed with cardiomyopathy and they will also require numerous veterinary check-ups and close at home monitoring.

The Future

Cardiomyopathy cannot be cured, although some research suggests that some of the changes of cardiomyopathy can be reversed if the disease is caught early enough. The goal of treating a cat with cardiomyopathy is to create a good quality of life and to allow you and your pet to spend some quality time together. Veterinary care and medications will be necessary to create this quality of life.

Unfortunately, cats are so good at hiding physical problems that when they finally show signs of cardiomyopathy, it is usually already well advanced and treatment options (and the cats' longevity) are often limited. Yearly veterinary wellness exams are your best method of catching the disease before it becomes too advanced; many cats with cardiomyopathy have heart murmurs that your veterinarian should be able to hear.