Arrythmia in Dogs

by Lydia Janssen
    Heart arrythmia can be a serious condition.

    Heart arrythmia can be a serious condition.

    John Howard/Digital Vision/Getty Images

    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

    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.

    Ventricular Arrhythmias

    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.

    Heart Block

    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.

    Photo Credits

    • John Howard/Digital Vision/Getty Images

    About the Author

    Lydia Janssen began her career writing news articles for the SPCA to connect adoptable pets with their potential owners. She moved into professional writing in 2009 and uses her experience as a dog trainer, SPCA kennel worker and veterinary technician to bring quality information to responsible pet owners.

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