Heart Disease in Dogs

Mixed breed dog at a vet's office
Heart disease can occur in any dog breed but some are at a higher risk of developing it.

Monty Rakusen/ Getty Images 

There are several different kinds of heart disease and while some dog breeds are at a higher risk of developing a heart problem than others, any dog can unfortunately get a heart problem. Because of this, it's helpful for owners to be able to recognize the signs of a potential issue. Knowing the causes, symptoms, and treatment options for heart disease can help you keep your dog's heart going strong for as long as possible.

What Is Heart Disease in Dogs?

A heart disease is any type of disease that affects the heart. The heart is an incredibly vital organ and if it is unable to function properly, multiple parts of the body will suffer. About 10% of all dogs examined by a veterinarian are found to have some type of heart disease and they often go undetected by their owners unless the disease is severe. Common diseases of the heart include:

  • Valvular Disease - Mitral valve issues are the most common type of valvular heart disease in dogs but tricuspid valve disease can also be seen. Valves are little flaps of tissue that act as doors between the chambers of the heart. These valves prevent blood from flowing backwards through the heart but when they do not work as they should, blood does not flow properly through the body.
  • Arrhythmogenic Right Ventricular Cardiomyopathy - Also referred to as Boxer cardiomyopathy due to the nearly exclusive occurrence in boxers, this is heart disease that causes an irregular heartbeat. The heart beats abnormally fast and blood is unable to be pumped throughout the body due to a change in the muscle in the right ventricle of the heart.
  • Heartworm Disease - Heartworms are passed through mosquitoes. When a mosquito bites a dog, the heartworm larvae enter the bloodstream. They grow and develop into worms that eventually fill the lungs and heart of a dog if a dog is not on an effective heartworm preventative.
  • Dilated Cardiomyopathy (DCM) - The heart is responsible for pumping blood through the body but in dogs with DCM, the heart has lost its ability to do this job effectively. DCM is very common in dogs and may go undetected for some time.
  • Myocarditis - If a dog has myocarditis, the heart has become inflamed and muscle cells are dying off.
  • Congenital Abnormalities - Some dogs are born with abnormalities or defects in their hearts that do not allow it to work properly. Examples of congenital heart disease include patent ductus arteriosus (shunt), pulmonic stenosis, aortic stenosis, persistent right aortic arch, and ventricular septal defect.

Congestive heart failure (CHF) is not a disease itself but rather the result of heart disease. Heart failure occurs when blood is no longer able to be adequately pumped throughout the body by the heart. Since some heart diseases are not able to be cured, they will eventually progress to heart failure.

Signs of Heart Disease in Dogs

Heart disease is often hidden since the heart is an internal organ but if it is severe enough, signs may be seen by a pet owner.

Symptoms

  • Coughing
  • Shortness of breath
  • Fatigue
  • Collapse
  • Distended or bloated abdomen
  • Pale or blue gums

Since the heart is responsible for pumping oxygenated blood throughout the body, breathing issues will often be seen in dogs with heart disease. Coughing, fatigue, and a shortness of breath are the most common signs but if the heart disease worsens, pale or blue gums, and even collapse will occur. Some dogs will also accumulate fluid in their abdomen as a result of heart disease. This will cause it to be enlarged and appear bloated and is referred to as ascites.

Causes of Heart Disease in Dogs

Heart disease can either be something a dog is born with or have develop during its life. Heart disease that develops during the life of a dog is a result of one or several of the following causes:

  • Heartworm infection from mosquitoes
  • Genetics
  • Various bacterial, viral and protozoal infections
  • Vitamin and mineral deficiencies
  • Toxins
  • Various medications
  • Tumors
  • Unknown

Dogs that have congenital heart disease can develop it in utero from one or several of the following causes:

  • Genetics
  • Medications taken by the pregnant mother
  • Environmental factors
  • Infection
  • Poisoning
  • Poor nutrition
  • Unknown

Diagnosing Heart Disease in Dogs

Since heart disease can easily go unnoticed, early stages of it may only be detected by your veterinarian. A full physical examination will be performed and your dog's breed, history, and any symptoms you are seeing or hearing at home will be taken into consideration. A stethoscope will be used to listen to your dog's heart and determine if a murmur or abnormal rhythm is able to be heard. If heart disease is suspected, chest X-rays, blood tests including a heartworm test, and an echocardiogram may be recommended. An electrocardiogram (ECG) may also be warranted depending on the type of heart disease that is suspected.

Treatment of Heart Disease in Dogs

Once heart disease is diagnosed, a treatment plan specific to the type of heart disease your dog has will be discussed. Heartworm disease is curable but requires strong medications to kill the heartworms inside your dog. Injections alongside pain medications are typically used and hospitalization to monitor for breathing difficulties may also be recommended. Other types of heart disease usually require life long monitoring with X-rays, echocardiograms, and ECG's as well as various medications. For some types of heart disease, surgery to fix a defect or remove a tumor may be an option.

How to Prevent Heart Disease in Dogs

If you are looking at getting a dog breed that is known to be more likely to develop heart disease than others, be sure to ask the breeder questions about the parents of your future dog. Dogs with genetic heart disease should not be bred.

Heartworm prevention should be administered year-round to all dogs to prevent heartworm disease, omega-3 fatty acids can be given to support heart health, and quality dog foods that follow the American Association of Feed Control Officials (AAFCO) guidelines should be fed to help avoid nutritional deficiencies. If you have a concern for specific nutritional deficiencies that are known to contribute to heart disease, such as carnitine and taurine, discuss which diet may be best for your specific dog. Medications with known side effects on the heart should not be administered without the need for them and avoiding exposure to toxins and contaminated areas should always occur.

At Risk Breeds for Heart Disease

Some dog breeds are known to be more likely to develop heart disease. These include:

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
Article Sources
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  1. Buchanan JW. Causes and prevalence of cardiovascular disease. Curr Vet Ther. 1992;XI:646.

  2. Buchanan JW. Causes and prevalence of cardiovascular disease. Curr Vet Ther. 1992;XI:646.

  3. Pyle RL, DF Patterson, S Chacko. The genetics and pathology of discrete subvalvular stenosis in the newfoundland dog. AHJ 92; 324-334, 1976