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Arrhythmia—Understanding Your Dog's Irregular Heartbeat

Arrhythmia in dogs is common, and many of our canine companions can live long, healthy lives even with this heart condition, but sadly that is not always the case. Our Newtown Veterinary Specialists vets look at the ins and outs of arrhythmia in dogs, signs to watch for, and treatment options.

About Arrhythmia

Arrhythmia in dogs is an abnormality in your pup's heart rhythm. Arrhythmia's irregularities can include the heart's speed, strength, or regularity of heartbeats. It is a condition generally caused by unusual electrical activity in your pup's heart muscle. Arrhythmia in dogs can be genetic and present from birth, or be the result of something that has occurred in your dog's life.

While any dog can suffer from arrhythmia, there are certain breeds that are predisposed to the condition, most notably brachycephalic breeds including bulldogs, Lhasa apsos, Pekingese, pugs, Shar-Peis, Shih Tzus, and boxers.

If your dog shows signs of having an unusual heartbeat, it is essential to contact your vet. Arrhythmia can be a sign of a serious underlying health condition that requires immediate treatment in order to avoid long-lasting side effects.

Here’s what you should know about the symptoms, causes, and treatments for dogs with heart arrhythmia.


Irregular heartbeat in dogs can be caused by a number of factors, including:

  • Genetics/hereditary
  • Age
  • Injuries
  • Infections
  • Stress
  • Gastrointestinal disease
  • Respiratory disease
  • Exposure to toxins
  • Electrolyte imbalance
  • Congestive heart failure
  • Congenital heart abnormalities (present from birth)
  • Heart disease
  • Diseases that affect the vagus nerves
  • Cerebral disorders
  • Conditions that cause pressure within the skull


There are three main signs of cardiac arrhythmia in dogs:

  • Weakness
  • Loss of consciousness
  • Long pauses between heartbeats


Heart arrhythmias in dogs fall into 5 main categories, they are:

  • Ventricular Arrhythmias (also known as Boxer Cardiomyopathy)
  • Atrial Fibrillation (Commonly seen in giant breeds such as Irish Wolfhounds and Great Danes)
  • Sick Sinus Syndrome (Often diagnosed in Miniature Schnauzers, West Highland White Terriers, and Cocker Spaniels)
  • Heart Block (A birth defect seen in Pugs, Cocker Spaniels, and Doberman Pinschers)
  • Myocarditis (Heart inflammation seen across all dog breeds)


Your dog's treatment will differ depending on the type of arrhythmia and the breed of your dog. Some possible treatment options are:

Complete physical exam - Your vet will listen to your dog’s heart using a stethoscope.

Electrocardiogram. Sometimes, there is a need to record the electrocardiograms and monitor them for 24 hours. The 24-hour monitoring period is necessary to determine the frequency and severity of the rhythm disturbance.

Your dog's arrhythmia will need ongoing monitoring and medication from your veterinarian to help ensure that your pup lives their best possible life. 

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

 Are you concerned that your dog may have a heart condition? Our Newtown veterinary specialists have advanced training in caring for dogs with complex needs. Contact us right away to learn more about our specialty care.

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Newtown Veterinary Specialists is accepting new patients! Our experienced vets are passionate about the health of Newtown companion animals. Get in touch today to book your pet's first appointment.

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