Arrythmia in Dogsby Lydia Janssen
Heart arrythmia includes any rhythm outside of the normal heartbeat, including a beat that is too fast, too slow or irregular. These conditions can include a number of different abnormalities, from a minor infection to a serious deformity of the heart walls and valves. The treatment of arrythmia will depend largely on what type of arrythmia it is and what is causing the condition.
Rapid or Slow Heartbeat
Many different conditions may cause a faster-than-normal heart rate, including anemia, infection, shock, blood loss, dehydration, heart disease or simple anxiety. A slow heart rate may also have a wide range of causes, including heart disease, pressure in the brain due to fluid or lesions, or a collapsing circulatory system due to infection or blockage. It is important to consult your veterinarian about these conditions, as the treatments are as varied as the causes.
Atrial fibrillation is a condition that may include an enlarged heart. In atrial fibrillation, the atria chambers of the heart beat irregularly, causing a rapid and irregular heart beat. It is most commonly seen in large breed dogs, especially great Danes, Newfoundlands, doberman pinschers and Irish wolfhounds. Medications such as dilitiazem or atenolol may be used to slow the rapid heart rate. Cardioversion, using electricity to encourage a regular heart beat, is usually only effective temporarily.
This condition consists of an irregular beat in the ventricle chambers of the heart, due to irritation. It may be caused by stretched heart fibers, insufficient oxygen to the heart or certain medications. The condition may be mild, consisting of one or two irregular beats, or severe, consisting of collapse, ventricular fibrillation, ventricular spasms and potentially death. The disease is more common in boxers, bulldogs and German shepherds. Drugs to treat the arrythmia, such as sotalol, may help, and the condition will generally disappear by the dog's second year of life.
Sick Sinus Syndrome
Sick sinus syndrome affects the sinus node, the part of the heart that tells it when to beat. The heart may beat too quickly or too slowly at different times, and will sometimes stop altogether for a brief period of time, leading to potential collapse and death. Other parts of the heart may compensate to encourage the muscle to start beating again during a long pause. Dogs with this condition will generally need a pacemaker implanted in order to lead normal lives. This condition is more common in Cocker spaniels, miniature schnauzers, dachshunds, and boxers.
In heart block, the sinus node does not tell the ventricles to contract at all. Generally a secondary source in the heart will make the ventricles contract, preventing sudden death. The heart rate is usually very slow, and dogs with this condition may be weak, unable to exercise and prone to collapse. Severe cases may result in heart failure. Dogs with this condition will need a pacemaker to correct the arrhythmia.
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