Cardiomyopathy in Dogs: What You Need to Know

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Your dog loves you with their whole heart, but what happens when their heart isn’t working as it should? Cardiomyopathy is a common heart disease among dogs, and by paying attention to any of your dog's symptoms and bringing them to the veterinarian for regular heart screenings, you can help detect these heart issues and more quickly begin treatment when possible.

There are two major types of cardiomyopathy dogs suffer from: Dilated cardiomyopathy (DCM), and Hypertrophic cardiomyopathy, which is less common in dogs than cats.

Dilated Cardiomyopathy in Dogs

Dilated cardiomyopathy is one of the most common heart diseases in dogs, according to the Pet Health Network. With DCM, heart muscles degenerate and wear thin. Thinner muscle walls decrease the heart’s contractility (how strong it can contract and pump blood), which effectively leads to congestive heart failure.

Though we don't entirely understand what causes DCM in dogs, this type of cardiomyopathy is most often diagnosed in large and giant breed dogs who are middle-aged and older. The disease is at least partly genetic, and nutrition may also play a part, according to the University of Illinois College of Veterinary Medicine. Breeds such as Doberman pinschers and boxers are also prone to breed-specific arrhythmias (irregular heartbeats) that may develop into DCM.

If you notice any of the following signs, you should have your dog checked for DCM:

  • Exercise intolerance and a general slowing down (common in the disease's early stages)
  • Feet are cool to the touch
  • Coughing
  • Pot-bellied appearance
  • Decreased appetite
  • Labored breathing

If your dog experiences rapid and heavy breathing, a blue tongue, or if they collapse, you should seek emergency veterinary treatment.

Hypertrophic Cardiomyopathy in Dogs

Hypertrophic cardiomyopathy (HCM) is more common among cats and rarely occurs in dogs. Unlike DCM, this disease is characterized by a thickening of one or more parts of the heart's walls. HCM has been reported in Airedales, Great Danes, Boston terriers, poodles, bulldogs, and pointers. If your dog has HCM, their vet may recommend treatment for congestive heart failure along with exercise restriction and nutritional therapy.

A dog with HCM might not show any particular signs, but if you notice any of the following, you should contact your veterinarian:

  • Fainting
  • Signs of heart failure, including cough and exercise intolerance

Occult Cardiomyopathy in Doberman Pinschers

Doberman in blue collar smiling, gives paw to human in a field.

Occult cardiomyopathy — a progressive disease that causes abnormal heart rhythms — affects a large number of adult Doberman pinschers.

Dobermans with occult cardiomyopathy may have no clinical signs for years until arrhythmias progress, and DCM may develop. Older dogs who develop DCM may experience exercise intolerance. Fainting or sudden death may also occur. The best way to avoid these outcomes is to take your Doberman for annual screenings, as they make it more likely that the disease will be detected, and the arrhythmia will be controlled.

Boxer Cardiomyopathy

Boxer dog sitting in green grass field intense look

Boxer cardiomyopathy, also called arrhythmogenic right ventricle cardiomyopathy, is a disease that affects a Boxer’s heart muscles and causes arrhythmias. These arrhythmias usually arise from the right ventricle, according to the Cornell University College of Veterinary Medicine. Fainting episodes or sudden death can occur.

Boxers usually don't show signs of the disease unless their arrhythmias become severe. Arrhythmias may be detected during physical exams or screenings for the condition.

Diagnosis of Cardiomyopathy in Dogs

Your dog's vet can listen to their heart with a stethoscope to identify abnormalities, but murmurs or irregular rhythms aren't always detectable. Further tests are needed to accurately diagnose cardiomyopathy, such as:

  • Chest radiographs
  • Blood and urine tests (to evaluate the function of organs that may be impaired as a result of heart disease)
  • An electrocardiogram
  • An ultrasound of the heart (also called an echocardiogram)

Treatment of Cardiomyopathy in Dogs

Cardiomyopathies can be serious diseases and should be diagnosed and treated appropriately. Most dogs with cardiomyopathy improve with treatment, and your veterinarian may prescribe one or more of the following medications:

  • Diuretics to help remove excess fluid from the body
  • Angiotensin-converting enzyme (ACE) inhibitors to lower blood pressure and make it easier for blood to flow out of the heart
  • Digitalis glycosides to help slow the heart rate and strengthen contractions
  • Vasodilators to dilate the arteries/veins and put less stress on the heart to pump blood
  • Pimobendan: Medicine with promising results in dogs with DCM.

Nutrition and Cardiomyopathy in Dogs

Your vet may recommend nutritional changes that can help manage cardiovascular health in your pet, including:

  • Controlled salt intake helps maintain normal blood pressure
  • Although taurine is not an essential nutrient for dogs, it can help support cardiac muscle metabolism. In several dog breeds, there is a strong link between taurine and dilated cardiomyopathy.
  • L-carnitine supports healthy heart function
  • B-vitamins magnesium may be lost in dogs that receiving diuretics
  • Avoiding an excess of protein or phosphorus, which can stress a pet’s kidney health in addition to their heart condition
  • Omega-3 fatty acids may help that is common in dogs with heart disease

Be sure to speak with your dog's vet before making any changes to their meal plan.

If you suspect your dog may have heart disease, it's crucial to work with your dog's vet to accurately diagnose and treat the condition. Many dogs with cardiomyopathy continue to live happy lives with hearts healthy to love their pet parents for years to come.

Contributor Bio

Dr. Laci Schaible

Dr. Laci Schaible, is a small-animal veterinarian and veterinary writer. She has won numerous awards for her commitment to pet owner education and is considered a leading veterinary telehealth expert.

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