Definition of Heartbeat Arrhythmia in Cats
A cardiac arrhythmia is a disturbance in the normal rhythm of the heart, either in frequency (beating too fast or too slow), in amplitude (beating too strongly or not strongly enough), in regularity (skipping beats), or most commonly in several or all of these areas. Arrhythmias can cause no medical problems or can be extremely serious and even life-threatening.
Symptoms of Heartbeat Arrhythmias Affect Cats
Many cats have a mild irregular heartbeat from time to time, especially if they are nervous, scared or stressed. This is considered fairly normal. Young cats that are diagnosed with an arrhythmia during a well-kitten veterinary visit may just be frightened by the unfamiliar people and place. This form of arrhythmia typically is a heart rhythm that is a bit too fast or which skips a beat from time to time. It is not considered especially serious.
The clinical signs of cardiac arrhythmias in cats can mimic a number of medical disorders. Cats with mild to moderate arrhythmias often show no clinical signs. When signs do appear, they can be very nonspecific. For example, the owner may notice that the cat is just not as active as usual, pants with activity or simply “poops out” with normal exertion. Severe arrhythmias can present with coughing, fainting spells, abdominal discomfort, rapid shallow breathing, fatigue, weakness, loss of appetite and even sudden death. It is not unusual for these signs to wax and wane in cats with underlying heart disease. When a veterinarian suspects that a patient may have a clinically relevant arrhythmia, a complete cardiac workup is usually recommended. The cardiac workup may include thoracic radiographs (chest x-rays), electrocardiography, echocardiography, blood work (a complete blood count and serum chemistry panel) and a urinalysis. These tests can help to identify or rule out any underlying medical conditions or primary heart abnormalities which may be causing or contributing to the heart rhythm irregularity.
If you notice any of these signs in your cat, take him or her to a veterinarian as soon as you can. Be thorough in describing what you observed, when you observed it and why you are concerned. Cardiac arrhythmias often can be managed with medication and lifestyle changes.
Causes of Heartbeat Arrhythmia in Cats
Cardiac arrhythmias can occur for many reasons, but fundamentally they involve abnormal electrical activity in heart muscle. Some cardiac rhythm disturbances are of no clinical significance, but others can be extremely serious and even fatal. The causes of heartbeat arrhythmia can include inherited or congenital defects, infections, injuries, ingestion of poisons or toxins, cancer, environmental stressors, kidney disease, hyperthyroidism, breed predisposition, anemia, heartworm infection, fever, hypothermia, nutritional deficiencies and a number of other conditions or disorders. Dietary deficiency in taurine, an essential amino acid for cats, can cause severe arrhythmias and heart disease – especially dilated cardiomyopathy. However, most high-quality commercial cat food diets now contain the daily recommendations of taurine, and today this is an uncommon cause of heart problems in well-fed cats. Some animals live a normal life with mild heartbeat disturbances, while others are affected much more severely.
Preventing Heartbeat Arrhythmias in Cats
Because the potential causes of heartbeat irregularities are so varied, there is no simple way to prevent them. Good dietary management, regular activity and annual veterinary check-ups will go a long way toward keeping companion cats fit and sound.
Treating Heartbeat Arrhythmia in Cats
Many cats have arrhythmias that are clinically insignificant and do not require treatment. Other cats suffer from severe arrhythmic episodes that can be fatal. If your cat has been diagnosed with an arrhythmia, the treatment plan will depend upon the cause and severity of the underlying condition.
Hyperthyroidism and kidney disease are two of the more common diseases that can be associated with arrhythmias in cats. Treating or at least managing the underlying disease can help to resolve the secondary arrhythmic condition. In many cases, the cause of the arrhythmia is unknown, and treatment must be based on the clinical signs shown by the cat.
Hypertrophic cardiomyopathy is another common heart condition in cats that often is accompanied by arrhythmias. There is no cure for this disease, but there are treatments available that can help reduce the symptoms and extend the duration and quality of affected cats’ lives. Atenolol and diltiazem are among the two most popular prescription treatments available; these medications can help relax and reduce the workload of cardiac muscle, decrease the heart rate and modulate irregular heart rhythms. A host of other drugs, including antiarrhythmic medications, are available as well, and frequently several medications are used in combination to treat these disorders. As with any therapy, a veterinarian is best qualified to assess affected companion animals and recommend the best treatment or management protocols. New medications are always being developed.
There are several advanced surgical procedures that may be available for dogs and cats with particular heart conditions. These procedures are expensive and must be performed by a veterinary cardiology specialist. They are not something that most owners consider simply due to an irregular heartbeat. The first procedure, called catheter ablation (intracardiac electrophysiologic mapping and radiofrequency catheter ablation of accessory pathways) basically destroys the presumably faulty electrical pathways in or around the heart that may be causing or contributing to the rhythm irregularities. This procedure is carried out by inserting catheters into the main blood vessels, advancing the catheters towards the heart and using an electrical impulse to essentially initiate an arrhythmia and then destroy the tissue that is causing the arrhythmia. It has been reportedly used in dogs successfully, but it is unclear whether it is presently available for use in cats.
Another possible surgical procedure involves use of a pacemaker. As in people, this procedure has been successful for controlling severe cardiac arrhythmias in some companion animals. Again, the efficacy of its use in cats is uncertain.
It is important for owners to remember that, as with heart murmurs, heartbeat abnormalities often go undetected for years, and many cats never show any signs of discomfort or distress. Moreover, cardiac arrhythmias often can be managed with medication and lifestyle changes.