What is Heart Disease?
Because heart disease often remains asymptomatic until heart failure occurs, it's important to schedule regular check-ups with the veterinarian in order to diagnose heart disease in its beginning stages when it's most treatable.
Heart disease is a serious condition that is diagnosed in approximately 10 percent of all cats. The disease can be congenital, meaning that the cat is born with the condition, or acquired, meaning that the condition developed throughout the cat's life. Though it's normally considered a primary disease that causes a variety of symptoms and other conditions to form, such as high blood pressure, heart disease can sometimes result from other diseases or conditions.
Symptoms of Heart Disease in Cats
Early detection is critical in the treatment of heart disease in cats, who tend to mask the symptoms longer than other small animals. These symptoms include:
- Weight loss
- Breathing difficulty
- Increased respiratory effort (shortness of breath)
- Increased respiratory rate
- Increased heart rate
- Blue-colored pads of the feet and nail beds
- Difficulty walking on hind legs (due to blood clots)
- Pain when walking
- Inability to tolerate exercise
- Withdrawn behavior
- Swollen abdomen
- Sudden death
Though there are several different forms of acquired heart disease, also known as feline cardiomyopathy, the three most common types are:
- Hypertrophic cardiomyopathy, which is characterized by a thickening of the heart muscle tissue in the left ventricle.
- Restrictive cardiomyopathy, which is characterized by a buildup of scar tissue on the inner lining of the left ventricle.
- Dilated cardiomyopathy, which is characterized by a dilated and poorly contracting left ventricle.
Causes of Heart Disease in Cats
Though the cause of feline cardiomyopathy isn't known, some breeds of cats are genetically predisposed to the condition. These breeds include Persians, Maine Coons, American Shorthairs and Ragdolls. Researchers believe that the disease may occur due to a genetic mutation.
Congenital heart disease in cats is typically caused by heart valve malformations, which prevent the heart valve from closing properly during pumping, and holes in the septa, which causes inappropriate blood flow between the chambers of the heart.
Diagnosis of Heart Disease in Cats
The veterinarian will need to know the cat's complete health history, a detailed list of all of the symptoms, an approximate date when the symptoms first began and any details that are known of the cat's genetic background. Other conditions, such as lung diseases, will need to be excluded in order to properly diagnose the cat with heart disease.
The veterinarian will listen to the cat's lungs and heart with a stethoscope, listening for wheezing, murmurs and other abnormal sounds. The cat's blood pressure and oxygen saturation will be measured. Blood tests, which will include a complete blood count and a biochemical profile, will also be done. These tests will look for anemia and other conditions, such as hyperthyroidism, that can cause cardiac symptoms similar to those of heart disease.
An electrocardiogram (EKG) will be performed on the cat to look at the electrical currents in the heart muscle. An EKG can help identify heart muscle damage and abnormal heart rhythms. An echocardiogram, also known as a heart ultrasound, will be done in order for the veterinarian to view the heart and look for any signs of muscle thickening, scar tissue or valve problems.
Treatment of Heart Disease in Cats
Though there is no cure for heart disease, there are a variety of medications available that can help control the cat's symptoms. Blood thinners, such as aspirin, may be prescribed to reduce the cat's risk of blood clots and prevent a heart attack or stroke from occurring. Blood pressure medications, such as ace inhibitors and beta-blockers, may be prescribed to improve blood flow, slow heart rhythm and stabilize irregular heart rates. Diuretics may be prescribed to help the cat's body shed excess water weight, which will put less pressure on the heart and help it to function better. Medications to dilate the arteries and ventricles to improve blood flow, such as nitroglycerin ointment, may also be prescribed by the veterinarian.
Cats who are having breathing difficulties may need to be hospitalized until their breathing and heart rates are stable. Oxygen therapy will be given in order to help the cat get necessary oxygen. This oxygen will be given to the cat either via a breathing mask or a nasal cannula. The oxygen will need to be continued until the prescribed medications are working well enough for the cat to get adequate oxygen on its own.
Because sodium can cause fluid retention, placing more work on the cat's heart, the cat will be prescribed a low-sodium diet in order to reduce water retention. If the cat has dilated cardiomyopathy due to a taurine deficiency, their diet will need to be changed to include more of this amino acid.
Recovery of Heart Disease in Cats
The cat will need to have stressors, such as other animals and small children, removed from its environment in order to recover properly. Because stress can place additional strain on the nervous system and heart, it's best to give the cat a safe and quiet space to rest. The cat should be kept warm in order to improve circulation. It's important to follow up with the veterinarian in order to monitor the cat's condition, look for any changes in the heart's function and evaluate the effectiveness of the prescribed medications.