Irregular Heart Rhythms in Cats

The heart is controlled by an electrical conduction system which controls the heart rate. This conduction system generates impulses, or waves, which flow through the muscles of the heart. A healthy heart muscle then contracts and pumps blood through the arteries and out into the body.

Irregular heart rhythm, or cardiac arrhythmia, is important to take note of, but is not always a serious condition. An irregular heartbeat occurs from time to time when a cat is under stress, nervous or scared. Some breeds, like Persians, Maine Coon cats and Himalayans, tend to be more prone to irregular heart rhythms than others.

An occasional irregular heart rhythm is not serious and will not cause health problems. However, a cat might exhibit irregular heartbeat due to early stages of heart disease, so it is wise to take your cat to the vet for an examination. Disturbance in the beating pattern may be the result of degeneration of the heart muscle or valves. Severe cases of irregular heartbeat can lead to the cat's brain being starved of oxygen because of the decreased blood flow. 

Irregular heart rhythms affect many cats and are characterized by an abnormality in the cycling of electrical impulses that regulate the heart's beating. This causes the heart to beat either too fast or too slow, or sometimes to skip beats.

Cats are very good at hiding problems. Especially because cats spend a lot of time sleeping already, a little less activity and more time spent napping might not be an obvious sign. In many cases, irregular heart rhythm can lead to changes in blood pressure and loss of blood flow to the cat's vital organs, and even heart failure. When signs do appear, they can be non-specific. It is also common for these signs to wax and wane. Common symptoms of irregular heart rhythm are: 

• Heart beats too slow
• Heart beats too fast
• Heart gallop (during a cycle of contractions, instead of the normal 2 beats, a third sound is audible)
• Heart murmur, due to turbulent blood flow within the heart
• Physical weakness, due to too long of a pause in between heart beats
• Depression
• Fatigue
• Loss of consciousness 
• Difficulty breathing
• Rapid breathing
• Pale gums
• Loss of appetite

Disturbance in a cat's heart rhythm has a variety of potential underlying causes. While heart diseases can be caused by an irregular rhythm, cardiac arrhythmia is not necessarily a sign that your cat suffers from heart disease. Some common causes of cardiac arrhythmia are:

• Hyperthyroidism (overactive thyroid)
• Hypertension (high blood pressure)
• An imbalance of electrolytes
• Anemia 
• Poor reaction to drugs
• Birth defects
• Low magnesium levels
• Taurine deficiency
• Low blood oxygen content
• Heart cancer
• Heart disease 
• Pancreatitis
• Heartworm infection
• Fever
• Hypothermia
• Ingestion of toxins

All cats should visit a vet at least once per year to detect any warning signs of heart disease like irregular heartbeat. Your veterinarian will use a stethoscope to listen to the cat's heartbeat and detect any abnormalities. A heart ultrasound examination (echocardiography) will also help the vet to analyze changes in the cardiac muscles. Your vet might also perform an electrocardiogram (ECG or EKG). Blood tests and blood pressure measurements can give the vet further insight into the underlying cause of the irregularity in heart rhythm. In some cases, a veterinary cardiologist might be recommended.

Most cats will be treated on an outpatient basis. Patients with an electrolyte imbalance will be hospitalized to receive intravenous fluid therapy. If an underlying cause of the arrhythmia is found, such as kidney disease or hyperthyroidism, then treating the underlying disease will resolve the irregular rhythm. The main goal of any treatment is to manage and eliminate any pain in the patient due to the abnormal rhythm, and to prevent extreme irregularities which might lead to death. 

Many medications can help control cardiac arrhythmia, some of which have side effects. In more serious cases, your vet might recommend one of several surgical procedures by a veterinary cardiologist. The most common procedure is installation of a pacemaker for long-term and better control of the arrhythmia.

Be proactive in caring for your cat's heart – during your regular visit, ask your vet for a proBNP blood test, a simple screening for heart disease. Help your cat maintain a healthy diet, and thereby a healthy heart, with optimal levels of protein, fats, and carbohydrates for their breed. Regular exercise and play also goes a long way towards keeping the heart healthy. 

If your cat has underlying structural damage causing the irregular heart rhythm or shows clinical signs of the arrhythmia such as fainting, you will be advised to restrict your cat's activity. Your vet will recommend regular follow-up examinations to evaluate heart rhythm and response to the treatment protocol. Blood work, EKG and echocardiography may be repeated. 

If your cat has only occasional irregular heartbeat and their health is not compromised in any way, no treatment is necessary other than regular yearly health checks by the vet.