Feline Heart Disease

Dr. Kari Mundschenk

Just For Cats Veterinary Hospital 

Heart disease in domestic cats is actually quite common.  It can strike at any age or any breed of cat.  One of the most challenging aspects of feline heart disease is that cats may not show any warning signs (such as exercise intolerance, coughing, and weakness) until the process is very advanced.  In most cases, coughing is not a sign of heart disease as it is in other species.  This means that a cat can literally be playing vigorously one day and suddenly have trouble breathing.  Untreated heart disease often progresses to heart failure, blood clot formation and death.

The detection of a new heart murmur by your veterinarian (often on routine examination) can be the first sign that changes in the heart have taken place.   While not every murmur signals the onset of heart disease, a further investigation is warranted since those murmurs which are a result of heart disease cannot be distinguished from "innocent" murmurs by routine tests alone.

Fortunately, advances in feline medicine enable veterinarians to efficiently diagnose cardiovascular disease in cats, even in its early stages.  In many instances, if heart disease is detected prior to the stage of actual heart failure, it can be successfully controlled with medications.  A feline with carefully controlled heart disease may live symptom free for years.

Cardiac disease can be brought on by primary (problem with the heart itself) or secondary disease (primary problem affects the heart).  The most common forms of heart disease in the cat include dilitative, hypertrophic, restrictive and arrhythmogenic right ventricular cardiomyopathy.  Common causes of primary diseases which lead to heart disease include those causing fluid retention such as the administration of corticosteroids, hyperthyroidism, hypertension, an elevated growth hormone level, tumors and myocarditis.  Fortunately, many of the aforementioned can be managed if caught early in the stage of disease.  There are genetic factors which can lead to heart disease.  Monitoring of the heart is used to determine when changes are occurring and when to start medicinal intervention.

The diagnosis and monitoring of cardiac disease is indicated in all kitties presented with a murmur.  Due to the potential severity of underlying disease, every cat should be worked up no matter how severe the murmur sounds.  These are the lucky cats as oftentimes, cardiac disease is present without a murmur.

Once cardiac disease is suspected or in those cats with a genetic predisposition to cardiac disease, a workup consisting of thoracic radiography, ultrasound or echocardiogram and an electrocardiogram will be recommended.  In certain breeds, a genetic test will be performed to verify if the kitty has the affected gene.  Doppler blood pressure is monitored in all kitties and lab work is evaluated as necessary.

Radiographs are used to evaluate overall heart size, check the lungs for edema and other changes and to check for free fluid in the chest.  In the case of an irregular rhythm, the electrocardiogram (ECG) is used to check the electrical conduction of the heart.  The ultrasound is used to definitively diagnose the type of cardiac disease in order to provide the best treatment.  The ultrasound allows the doctor to visualize the heart in motion, measure muscle and chamber size, check for blood clots and tumors, and to check for fluid in the chest or in the sac around the heart.

Once the type and severity of heart disease is determined, treatment can be tailored to your cat.  Obviously, if underlying disease such as hyperthyroidism or hypertension is present, those diseases need to be managed also.  There are medications to slow the heart rate and provide relaxation to the heart (atenolol), medications to reduce blood pressure (amlodipine, benazepril) and medications to decrease the blood volume (furosemide).  If fluid needs to be drained from the thorax, a needle will be inserted to allow drainage and a chest tube may be placed.

Your doctor will monitor your cat's heart at each visit and during surgical procedures.  If on fluid therapy, it will be performed in a way to decrease the load on the heart while treating the concurrent problem.  Diet may be employed as a way to keep the salt under control.  Finally any medications prescribed or used in your cat will be adjusted to ease the stress on the heart.

Just as in people, cats can live with heart disease.  Early detection, diagnosis and timing of therapy assist cats on a day to day basis.  Our goal is to realize the problem exists, diagnose and treat.