Cardiac arrhythmia refers to an abnormality of the heartbeat rate or pattern. The condition can be caused by trauma, a tumor, and a wide variety of diseases. It can result in weakness, depression, difficulty breathing, and even death. There are medications to control arrhythmia, but if a specific disease is the cause, simply addressing it might well remedy the problem.


A cardiac arrhythmia is an abnormality in a cat’s heartbeat. It can be associated with the rate (too fast or too slow), an irregularity in the heartbeat pattern, or a problem in the location where electrical signals are formed in the heart. Some arrhythmias may be harmless and don’t require treatment, while others can be serious and life threatening.

There are many types of heart rhythm disturbances and plenty of potential causes. While heart disease can cause an arrhythmia, an arrhythmia doesn’t necessarily indicate that a cat is suffering from a heart condition. Other causes of heart arrhythmias include:

  • Hyperthyroidism (too much thyroid hormone in the blood)
  • Imbalances in electrolytes
  • Anemia
  • Drug reactions
  • Tumors
  • Trauma

Cats of any breed, age, or sex may experience arrhythmias.

Symptoms and Identification

Cats with arrhythmias that are relatively harmless may show no outward signs. In many cases, however, an arrhythmia can lead to heart failure, changes in blood pressure, and alterations in blood flow to vital organs. Cats with these types of arrhythmias may show signs such as:

  • Weakness, depression
  • Difficulty breathing
  • Pale gums
  • Collapse
  • Sudden death

A veterinarian may note an irregularity in the heartbeat when listening to your pet’s heart with a stethoscope. An electrocardiogram (ECG or EKG) can provide additional information to further define the type of arrhythmia present.

If a veterinarian suspects that the abnormality in rhythm is caused by a heart condition, he or she may recommend chest radiographs (X-rays) and/or an echocardiogram, which is an examination of the heart using ultrasound equipment. Depending on a cat’s condition, a veterinary cardiologist might be recommended.

Since many other problems besides heart disease can cause cardiac arrhythmias, blood work and a urinalysis are fundamental tests typically undertaken to help rule out underlying diseases or conditions.

Affected Breeds

Certain breeds are predisposed to inherited conditions that can lead to heartbeat abnormalities. For example, Maine Coon cats and Persian cats seem predisposed to developing cardiomyopathy (a problem with the heart muscle that can be associated with changes in heart rate and rhythm).


If the arrhythmia is caused by an underlying condition, such as hyperthyroidism, treating the underlying disease may help resolve the arrhythmia. Otherwise, the goal of treatment is to eliminate or manage any discomfort experienced by the patient and to prevent dangerous arrhythmias from leading to sudden death.

Numerous medications can help control arrhythmias. Many of these drugs have side effects. In some cases it’s recommended that a pacemaker be implanted for long-term control of the arrhythmia.

Once a cat is diagnosed with an arrhythmia, veterinarians will almost always recommend periodic recheck examinations to evaluate heart rate/rhythm and assess a pet’s response to treatment. Blood work, X-rays, ECG, echocardiography, and other diagnostic tests sometimes need to be repeated periodically.


There is no known means of prevention of feline cardiac arrhythmias save judicious breeding (or not breeding, as the case may be) of cats affected by any inherited diseases that can lead to arrhythmia.

This article has been reviewed by a Veterinarian.