Just like us, some dogs develop heart disease. What might surprise you is that they don’t experience heart attacks (myocardial infarctions). This is likely because dogs don’t live for the multiple decades necessary for coronary artery plaque to accumulate. (They also don’t smoke cigarettes.)

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Breed-Specific Diseases

Certain breeds are particularly predisposed to heart disease. Cavalier King Charles Spaniels are the poster children for this, with more than half developing mitral valve disease by the age of five, and nearly 100% by age ten. Some of the other breeds at increased risk include: boxers, Doberman pinschers, great Danes, cocker spaniels, miniature and toy poodles, and miniature schnauzers.

Congenital (Birth) Defects

This category includes faulty heart valves, defects in the walls between heart chambers, and abnormally configured blood vessels. These defects alter normal blood flow in and around the heart.

Heartworm Disease

Mosquitos transmit this disease in which long spaghetti-like worms set up housekeeping within the heart and arteries that supply the lungs. Left untreated, heartworm disease causes heart and lung issues.

Valvular Disease

Valves open and close to control normal blood flow between the four chambers of the heart. Age-related heart valve degeneration occurs commonly, particularly in small breed dogs. The resulting “valvular insufficiency” can lead to heart failure. Endocarditis, a relatively uncommon disease, results from a bacterial infection that develops on one or more of the heart valves and alters normal blood flow.

Cardiomyopathy

This is disease within the heart muscle causing it to become too thin and flabby (dilated cardiomyopathy) or too thick and stiff (hypertrophic cardiomyopathy). Both conditions impair the normal pumping action of the heart.

Arrhythmias

Arrhythmias are alterations of the normal rhythm of heartbeats. An abnormal beat here and there isn’t a problem, but multiple abnormal beats interfere with blood flow and can produce significant symptoms.

The heart is a muscular pump responsible for circulating oxygen-rich blood throughout the body. When the pump fails (heart failure), not only can abnormal fluid accumulate in the body, dogs can develop symptoms caused by too little oxygen.

Early warning signs of heart disease can include: increased respiratory rate, coughing, lethargy, restlessness during sleep, and decreased stamina.

More advanced heart disease can cause: weakness, loss of appetite, labored breathing, distention of the abdomen with fluid, blue/purple tinged tongue and gums, fainting, collapse, and even sudden death.

Veterinarians use the following tests to confirm the diagnosis and type of heart disease:

• A thorough physical examination that includes auscultation of the chest cavity (listening to the heart and lungs with a stethoscope)

• Blood tests, including screening for heartworm disease

• An electrocardiogram (ECG) to evaluate the rhythm of the heartbeats

• Chest X-rays to evaluate the size of the heart and identify abnormal fluid in or around the lungs

• An echocardiogram (ultrasound evaluation of the heart) to evaluate valve function, chamber size, and the strength of heart contractions

While most canine heart diseases are not curable, they can often be successfully treated, even over a long period of time. Medications are the mainstay of treatment. They’re used to mobilize excess fluid accumulating in the chest, lungs, and/or abdomen. Drugs are also used to decrease the workload on the heart, enhance the strength of heart contractions, and prevent blood clots. Antiarrhythmics are used to treat abnormal heart rhythms, and antiparasitic drugs are used for heartworm disease.

Some types of heart disease are best treated with surgery or a specialized interventional procedure. Examples include placement of pacemakers, repair of a defective heart valve, and correction of birth defects.

A thorough physical examination performed by a veterinarian once a year (twice yearly for senior dogs) allows for early disease detection. In general, the earlier heart disease is detected, the better the long-term outcome. Given the inherited nature of some heart diseases, certain breeds of dogs should be screened prior to being used for breeding.

Heartworm disease is reliably preventable with monthly heartworm preventive medication.

If your four-legged best friend has heart disease, here are some important questions to ask your veterinarian.

• What type of heart disease does my dog have?

• How is it best treated?

• How will I know if treatment is working?

• What symptoms should I be watching for?

• When should I schedule a recheck for my dog?

• Consider asking for a referral to a veterinarian who specializes in cardiology, internal medicine, or radiology. An echocardiogram and other advanced cardiac procedures require specialized equipment and skills.

Has a dog of yours had heart disease? If so, was treatment required?

Best wishes to you and your four-legged family members for abundant good health,

Dr. Nancy

DrNancyKay.com

Speaking for Spot - Dr. Nancy Kay is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.