By Dr. Becker
Heart disease isn’t as common in kitties as it is in dogs, but it does occur. If you’re owned by a cat, it’s important to know what types of heart problems your pet may encounter. In some cases of feline heart disease, the signs are obvious to the trained eye (typically your veterinarian). But sometimes a serious heart disorder can remain hidden for years before it suddenly expresses itself – sometimes with catastrophic results.
There are two types of feline heart defects – congenital, and acquired.
Congenital Heart Defects in Cats
In congenital heart disease, the problem is present at birth. And while signs of a problem often appear at a young age, in some kitties congenital heart disease can go undetected for years. In fact, some cases of what looks like adult onset (acquired) heart disease turn out to be the result of an inherited condition that progressed as the cat aged, eventually causing symptoms.
Congenital heart disease can be caused by a malformation of the heart that occurs as a kitten develops in utero. This type of defect may affect only one kitten in the litter. Congenital heart disease can also be caused by an inherited disorder, in which case more than one kitten is often affected.
Fortunately, congenital cardiac disease is relatively rare in cats, occurring in only one to two percent of kittens. The most common congenital disorders are heart valve malformations (typically the mitral valve) that result in blood leaking backwards into the atrium of the heart, and holes in the septa.1
The prognosis for a kitten with a congenital cardiac disorder depends on the severity of the defect. Minor defects may not affect a cat’s life at all, while more serious disorders usually require medical treatment. The most severe defects typically carry a poor prognosis.
Acquired Feline Heart Disease
Adult onset heart disease in cats is the result of damage to the heart structure that occurs over time. The most common type of acquired heart disease in kitties is cardiomyopathy, which accounts for about two-thirds of feline heart conditions. Cardiomyopathy is a structural abnormality in the muscle surrounding one or both chambers of the heart, with the result that the left ventricle (and once in awhile, the right ventricle as well) becomes thickened, dilated or scarred.
The abnormality also interferes with the heart’s ability to collect and pump blood, which can lead to congestive heart failure and fluid in or around the lungs. Other complications of cardiomyopathy include blood clots that cause paralysis, and sudden death.
It is thought that both genetics and lifestyle (weight, diet, and physical activity) play a role in the development of feline cardiomyopathy. Occasionally, the condition develops secondarily to another disorder such as anemia, hyperthyroidism, or high blood pressure.
Three types of heart disease account for almost all the primary cardiomyopathies diagnosed in cats: hypertrophic cardiomyopathy, restrictive cardiomyopathy, and dilated cardiomyopathy.
Hypertrophic cardiomyopathy (HCM) is by far the most common type of primary heart disease in kitties, accounting for 85 to 90 percent of all cases.
The word "hypertrophic" means thickened, so this is a condition where the walls and ventricles of the heart become too thick, or hypertrophied. HCM is often inherited in cats. In fact, there's a test available now for a specific gene mutation in Maine Coons and Ragdolls. Purebred cats such as the Persian, other oriental breeds, and American shorthairs are also predisposed to develop the condition.
However, it's the regular house cat that is most commonly diagnosed with HCM. Cats usually develop the condition in midlife, but it can occur at any age.
Restrictive cardiomyopathy accounts for approximately 10 percent of primary heart muscle diseases in kitties and is most often seen in geriatric cats.
The condition is caused by an accumulation of scar tissue on the inner lining and muscle of a ventricle. The scar tissue buildup prevents the heart muscle from relaxing completely, and interferes with blood flow in and out of the ventricle. The disorder also results in severely enlarged atria (the top two chambers of the heart).
Dilated cardiomyopathy is more common in dogs than cats, and probably accounts for only one to two percent of primary cardiomyopathy cases in kitties. This is a disorder in which the left ventricle is enlarged and doesn’t contract effectively. The heart walls are thin and lax, which results in weak pumping and reduced forward flow of blood from the heart.
Other Types of Heart Disease in Cats
While cardiomyopathy is by far the most common form of primary heart disease in kitties, there are other types of cardiac issues that can also affect your cat, including:
- Heart murmur. Heart murmurs are caused by turbulent blood flow within the heart or the large vessels exiting the heart. This choppy blood flow causes an abnormal noise that your vet can hear with a stethoscope.
- Cardiac arrhythmia. A cardiac arrhythmia is an abnormal heartbeat that can be characterized by a too fast or too slow heart rate, an irregularity in the heartbeat pattern, or a problem in the location where electrical signals are formed in the heart. Some arrhythmias are harmless and don’t require treatment, while others can be serious and even life threatening. There are many potential causes of heart rhythm disturbances, and it’s possible a kitty’s arrhythmia isn’t even an indicator of a heart condition. Causes of cardiac arrhythmias in cats include hyperthyroidism, electrolyte imbalances, anemia, drug reactions, tumors, and trauma.
- Congestive heart failure. When a cat’s heart can’t pump enough blood to the body, fluid backs up into the lungs, and congestive heart failure is the result. There are many causes of congestive heart failure in cats, but most often it results from hypertrophic cardiomyopathy. Thyroid disease, high blood pressure, birth defects, and other conditions can also cause congestive heart failure.
Tips to Proactively Protect Your Cat’s Heart Health
Ask your veterinarian for a proBNP blood test. This test can give you peace of mind that your kitty has no early signs of heart disease. It’s a simple blood test with a fast turn-around time that can provide the information you need to proactively manage your cat’s heart health.
Help your cat maintain a lean, fit body by feeding a balanced, species-appropriate diet that meets your pet's nutritional requirements for optimal protein levels, healthy fat and coenzyme Q10.
I firmly believe the unnecessary carbohydrates found in most cats foods offsets the amount of protein cats need, making carbs a significant nutritional contributing factor to feline heart disease. The amount of taurine, carnitine and CoQ10 found naturally in unprocessed meat is critically important to feline heart health. In my opinion, these vital nutrients are not found in adequate quantities in most dry foods, and processing further diminishes their bioavailability. This is another reason I recommend starch free foods (no grains or potatoes) for cats.
If you feed dry or canned food, I recommend you supplement your pet’s diet with coenzyme Q10 in the form of ubiquinol, especially if you have a cat that may be predisposed to cardiovascular disease. Supplying your pet with extra CoQ10 (the reduced form) can insure she has the quantity her body needs to maintain a healthy heart muscle.