What Is Degenerative Mitral Valve Disease, and Does It Affect Your Dog?

PETA member and founder of the American Vitiligo Research Foundation Inc. (AVRF) Stella Pavlides—who persuaded the head of the Department of Dermatology at Harvard Medical School not to test on animals while researching treatments for vitiligo in 2019—has a soft spot for elderly dogs, sick dogs, and even dogs with a bit of a chip on their shoulders, like her lovable scamp, Buster. But while Stella’s heart is firmly in the right place, her beloved dog Joey’s isn’t in great shape.

When Stella adopted Joey three years ago, the spunky senior Jack Russell mix was suffering from a respiratory infection and coughing up green phlegm. The infection quickly cleared up with medication, but during his exam, the vet discovered a heart murmur caused by something that wasn’t going to be so easily resolved—degenerative mitral valve disease (DMVD).

You may never have heard of DMVD, but according to Dr. Simon Swift, a veterinary cardiologist at the University of Florida, it’s the most common heart disease in dogs, affecting an estimated 5 to 7 million of them in the U.S.—usually older dogs and smaller breeds. For example, experts estimate that virtually all Cavalier King Charles Spaniels will develop the disease at some point in their lives.

What Is DMVD?

DMVD occurs when the mitral valve in the heart thickens and/or loses elasticity and doesn’t close properly, causing blood in the heart to flow backward (mitral regurgitation). As the disease progresses, the heart may become enlarged and/or fluid may accumulate in the lungs and abdomen.

How Can I Tell if My Dog Has DMVD?

In the early stages, many dogs have few discernable symptoms—but as congestive heart failure develops, symptoms may include coughing, rapid or labored breathing, lethargy, lack of appetite, fainting, and intolerance of exercise. Your veterinarian can perform various tests to diagnose DMVD, including X-rays, blood and urine tests, electrocardiograms, and echocardiograms.

What Causes DMVD?

As a dog ages, the mitral valve may begin to wear out and leak. Other causes include ruptures of the cords that hold the valve in position or bacterial or viral infections that reach the heart (often associated with chronic periodontal disease).

How Is DMVD Treated?

There is no cure for DMVD other than a highly complex and expensive surgery, which is not a viable solution for most dogs and their guardians. Only one surgeon in the world—Dr. Masami Uechi in Japan—has a high rate of success with this procedure, although the University of Florida and other facilities are hoping to receive training from his team to implement his technique. However, if the disease is caught during its early stages, dogs can survive for years with the help of medications, including diuretics, inotropes, vasodilators, and angiotensin-converting enzyme inhibitors.

How Can I Protect My Dog?

Keep an eye on your dog for signs of “slowing down”—which can signal the early stages of DMVD or other serious diseases—and be sure to see a vet for regular checkups, especially if your dog is 7 years old or more. Since dental infections can lead to heart infections, maintain your dog’s oral health and brush his or her teeth daily. To reduce the strain on your dog’s heart, make sure that he or she maintains a healthy weight—your vet can advise you on implementing a weight-loss program, if necessary.


As any loving guardian would, Stella is spreading the word and doing all that she can to support Joey’s heart health and to help all dogs suffering from DMVD and other heart diseases. With increased awareness, more veterinary surgeons in the U.S. will be able to treat dogs like Joey successfully—helping many hearts heal in the process.