Atrioventricular Valvular Insufficiency (AVVI) or mitral valve disease is the most common form of heart disease in the dog. Three quarters (75%) of the cases of canine heart disease in North America are caused by chronic valve disease.1
As the name suggests, this disease affects one or more of the heart valves. Heart valves normally form a perfect seal when closed. However, in valve disease one or more of these valves "leak," allowing blood to be pumped backwards. This backward flow creates a noise, called a murmur, which your vet can hear with a stethoscope. Listen to a heart murmur.