These diseases are thought to be hereditary.
Atrioventricular abnormalities occur most frequently in large and giant breeds of dog including the German Shepherd Dog , Great Dane Labrador Retriever and Old English Sheepdog . Mitral stenosis has been reported in the English Bull Terrier in the UK.
Endocardial cushion defects are quite common in cats and may also involve defects (holes) in the septum separating the two atria (atrial septal defects), and notched or cleft atrioventricular valves. Tricuspid valve dysplasia is reported to be common in domestic shorthaired cats.
Echocardiography provides a definitive diagnosis
The only form of long-term treatment is open heart surgery and replacement of the affected valve but there are very few veterinary centres in which this procedure is performed routinely.
Long term problems
Updated January 2016