4 Dangers of an Enlarged Heart in Dogs Having a Large Heart Isn't Always a Good Thing

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An englarged heart in dogs can be potentially fatal if not diagnosed and treated promptly. So it's important to know the causes, symptoms, and possible dangers of an enlarged heart.

Heart health can be a big concern for dog owners, especially those who are raising certain breeds. For instance, the Doberman Pinscher, Boxer, Scottish Deerhound, Irish Wolfhound, Great Dane, Saint Bernard, Afghan Hound, and Cocker Spaniel all have a greater risk of developing an enlarged heart, also known as dilated cardiomyopathy (DCM), as compared to other breeds.

An enlarged heart in dogs develops when the heart’s muscles weaken, causing pressure in the heart’s blood vessels to increase and, in turn, stretching the muscles. Valvular defects, heartbeat abnormalities, tumors, and heartworms can all be behind the initial weakening of the muscles.

When these muscles enlarge, a number of dangers can follow, such as:

1. Heart Murmur / Arrhythmias

Due to the enlarged muscles, the heart’s valves cannot close completely, causing blood to flow backwards, thus creating a murmur. Arrhythmias occur when the electrical impulses of the heart don't work properly, causing an irregular heartbeat. These impulses can be thrown off as the muscles enlarge.

2. Distended Abdomen

A distended abdomen will typically occur when the muscles on the right side of the heart enlarge so much that they fail and fluid begins to build up in the abdomen. This buildup then puts pressure on the diaphragm, causing trouble breathing. You might also notice your dog eating less or occasionally vomiting, both of which can lead to weight loss and malnutrition.

3. Fluid in the Lungs

Fluid in the lungs will typically occur when the muscles in the left side of the heart enlarge so much that they fail, causing fluid to pool in the lungs. This buildup then fills space in the lungs needed to bring oxygen into the bloodstream. In addition to causing a lingering cough, heavy breathing, fatigue, fainting, and even a bluing of the lips or tongue, fluid buildup in the lungs can also result in death.

4. Heart Failure

Congestive heart failure occurs when the heart’s muscles enlarge to a point at which they can no longer meet the circulatory demands of the body, often resulting in death.

Enlarged hearts, if they do develop, normally develop in dogs between 4 to 10 years of age and can be found via a radiograph of the chest. The severity of the condition is determined with an ultrasound, which will show how much muscle function is left. However, your vet may spot the condition during a thorough physical exam.

Depending on how severe the condition is, your vet can prescribe medication to help the heart contract more effectively. They will also schedule regular checkups to track any progress, which can be determined with radiographs, blood pressure measurements, EKGs and biochemical tests.

Unfortunately, in most cases, by the time the condition is spotted and diagnosed it is too late -- life expectancy is usually determined to be under six months. But within those months, your vet can best advise you how to make your dog's life as comfortable as possible.

More on Heart Health

7 Risk Factors for Congestive Heart Failure in Dogs
Nutrition for Cats and Dogs With Heart Disease
Heart Disease in Dogs and Cats

This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

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