Feline Heart Disease
Any cat can develop heart disease, so it is always wise to have regular veterinary checkups. There are several reasons that cats may develop heart disease, some congenital and some acquired. Whatever the cause, early detection is almost always an advantage in protecting the cat's heart from further damage and prolonging its life.
Congenital Heart Defects
While congenital heart defects are relatively rare in cats, occurring in only one to two percent of newborn kittens, they can be very serious. The most common feline congenital heart defects are malformations of the heart valves and holes in the septa, the walls separating the chambers of the heart from one another.
Ordinarily, when there is a valvular problem, it occurs in the mitral valve, the one between the left atrium (upper chamber) and the left ventricle (lower chamber). Either type of congenital defect usually permits leakage or inappropriate blood flow, allowing oxygenated and deoxygenated blood to mix.
Although kittens generally respond well to medication therapy, prognosis for surgical correction may be poor. With proper medication and regular monitoring, most kittens with minor congenital defects can look forward to normal, happy lives.
Acquired Disorders
Cardiomyopathy, most often an acquired condition, is by far the most common heart disorder in adult cats. About two-thirds of all cats diagnosed with heart conditions have cardiomyopathy which involves an abnormality of the muscle surrounding the left ventricle of the heart. Rarely, the right ventricle is affected as well. When cardiomyopathy occurs, the ventricle becomes thickened or scarred in appearance, negatively impacting the heart's circulatory and pumping functions.
Eventually, cardiomyopathy can progress to congestive heart failure (CHF), as fluid collects in and around the lungs, resulting in respiratory distress. Cardiomyopathy can also cause paralyzing blood clots and sudden death.
Feline cardiomyopathy is categorized as either primary (genetic or idiopathic) or secondary, originating from another condition such as anemia or hypertension. The primary form of this disorder is much more common and is subdivided into three categories:
Hypertrophic Cardiomyopathy
The vast majority (85 to 90 percent) of cases of cardiomyopathy fall into this category. Characterized by a thickening of the muscle associated with the left ventricle, hypertrophic cardiomyopathy is suspected of having a strong hereditary component. Hypertrophic cardiomyopathy is found more commonly in Persian, Ragdolls and Maine Coons.
Restrictive Cardiomyopathy
Restrictive cardiomyopathy, caused by a buildup of excessive scar tissue in the lining and on the muscle of the left ventricle, is responsible for about 10 percent of feline cardiomyopathy cases. The scar tissue prevents the heart from relaxing adequately to fill and empty with each heartbeat. This type of cardiomyopathy usually affects older cats.
Dilated Cardiomyopathy
Dilated cardiomyopathy, is a rare type of primary cardiomyopathy, defined by an enlarged left ventricle with weak contractual ability. This category of the disorder affects only 1 to 2 percent of cats with primary cardiomyopathy.
Other varieties of acquired feline heart disease include feline myocarditis and myocardial infarction.
Symptoms of Feline Heart Disease
Cats often disguise their symptoms of heart disease better than dogs. The two major symptoms of advanced heart disease in cats are difficulty breathing and difficulty walking. The cats may also vomit. If there is a clot present, the cat's back legs may suddenly become paralyzed. When a cat exhibits any of these symptoms, immediate veterinary care should be sought. Clots are especially dangerous in cats and, while they may dissolve on their own, they may reoccur.
Diagnosis of Feline Heart Disease
As noted, most feline heart disease is first diagnosed with the doctor's stethoscope with which heart murmurs or other abnormal sounds can be detected. Blood pressure irregularities are also evidence of possible heart irregularities. Other tests for feline heart disease include:
- X-rays
- Electrocardiogram (EKG)
- Echocardiogram
- Blood work
Blood tests may also show other conditions which may be the underlying cause of the cat's heart symptoms.
Treatment of Feline Heart Disease
There are several varieties of medications that may be helpful in treating heart disease in cats, depending on its severity. These include:
- Beta-blockers
- Heart muscle relaxers
- Diuretics
- ACE inhibitors
- Blood thinners
It is not always possible to predict which cats will do well on which medications. Some cats can live comfortably for many years with heart disease while others may develop complications or die suddenly.