My veterinarian told me that my three-year old cat has an irregular heartbeat. The doctor said it was not serious and that I shouldn't worry. Could an irregular heartbeat lead to any serious problems for my cat in the future?
Arrhythmias, or irregular heartbeats, are physiological responses to underlying disease processes or disorders. Such disorders may arise in the heart itself or in another location of the body. An example of the latter would be a kidney disease-associated elevation in the blood's potassium level that can cause an arrhythmia that can result in asystole (the heart stops). An irregular heartbeat can be an incidental finding in some animals or may be an indicator of a serious problem.
Arrhythmias are detectable on electrocardiograms (ECG or EKG). Some arrhythmias are associated with changes in the normal heart sounds heard through a stethoscope. Many will also present as either faster (tachyarrhythmia) or slower (bradyarrhythmia) than the normal heart rate.
The normal heart rate for cats is 160 to 240 beats per minute. An excessively fast heart rate (tachycardia) is a heart rate greater than 240. An abnormally slow rate (bradycardia) is one below 160. Both tachyarrhythmias and bradyarrhythmias may be associated with pathophysiologic processes that cause hypoxia, or low blood-oxygen concentration.
Signs of clinically significant arrhythmias may include varying degrees of weakness, fatigue, and exercise intolerance, depending on the severity of the condition. Patients with severe disease may have a wobbly gait, fainting spells, and seizures. In severe cases death may result.
In a young cat, an arrhythmia called a gallop rhythm may occur and is not considered to be a problem, especially if the cat is nervous. Many times, the irregular beat is temporary, occurring during times of stress or anxiety. This sounds like what your veterinarian probably detected in your cat. These arrhythmias seem to have no ill effects on the cat's condition for the long term.
Your veterinarian will listen to your cat's heart at each physical exam visit and will let you know if there are any changes. Certain arrhythmias can indicate primary heart disease, but these typically are more commonly detected in older cats or have been present since birth.
If your veterinarian becomes concerned, he or she will probably recommend a cardiac work-up. This usually involves chest x-rays, an EKG, and sometimes an ultrasound study of the heart. Veterinary cardiologists are available for those patients that need referral.
04/11/01
