Mitral Valve Disease
Mitral valve disease (MVD) is a condition whereby the mitral valve thickens and degrades overtime. A leak in the valve develops as the valve can no longer close properly. MVD is considered an older age, acquired disease and is very common in small breed of dogs. The first sign that your dog has MVD is a heart murmur. It is a slowly progressive disease and dogs are often asymptomatic for many years. As the disease progresses, dogs will go on to develop other symptoms including coughing, lethargy, exercise intolerance, and, in some cases, fainting. Eventually MVD leads to congestive heart failure.
While MVD cannot be cured, it can be treated for a long period of time with good quality of life—even when the dog enters heart failure. An echocardiogram is used to definitely diagnosis the disease and as the gold standard for timing medications as the disease progresses. Chest radiographs are often used in conjunction with the echocardiogram to look for any fluid in the lungs and overall heart size. And an ECG may also be advised to examine the dog’s heart rhythm (electrical activity).
From a breeding standpoint, the concern is young age onset of MVD. It is advised the Chihuahuas used in a breeding program be screened by auscultation annually.
AKC CHF Podcast: What to Expect when you visit a Veterinary Cardiologist