Mitral valve insufficiency: Let’s have a look at this common heart disease in older, small breed dogs.

As you can probably tell from its name, mitral valve insufficiency is a disease that effects the mitral valves, located between the left atrium and left ventricle, and causes functional insufficiency. The heart has four chambers, and each chamber is separated by a set of valves. The valves open and close systematically to keep blood from flowing backwards. However, when the valve does not close completely, blood regurgitates and causes circulatory failure.

Common breeds

Older, small breed dogs such as the Chihuahua, Maltese and Shih Tzu are common breeds for this disease. Cavalier King Charles Spaniels are likely to develop this disease genetically, even at a young age.

Cause

Deformation of the valve / heart.

Symptoms

Only a heart murmur will be detected and is asymptomatic in early stages of the disease. As it progresses, blood regurgitates and the causes congestion in the heart. Congestion leads to enlargement of the heart, which then presses up against the trachea, causing the affected animal to cough. As blood circulation worsens, dogs will become exercise intolerant. In the next stage of the disease, blood in the lungs will congest as well and lead to pulmonary edema. This situation leads to oxygen deficiency and symptoms such as discoloration of the tongue, respiratory distress and syncope may be observed. In the worst case, it may even lead to death.

Examination

The first step would be to check for heart murmurs with auscultation. Additionally, electrocardiogram, blood pressure measurement, blood test, ultrasonography and chest X-ray will aid in determining the stage of disease, including level of regurgitation and status of the lungs.

Treatment

Treatment will be based on assessment of cardiac function.

Even if symptoms improve temporarily, it is important that pet owners don’t stop medication based on their own judgement. And always remember, if symptoms worsen, to consult your vet immediately.

Lastly

This is a progressive disease and is impossible to prevent or cure, but it is possible to slow down the speed of progression with early detection. In early stages of disease, there may be no visible symptoms despite having a heart murmur, so even if your dog looks healthy, regular checkups at your local vet come in handy. Owners of high-risk breeds or mid/old age pets should consider full annual checkups as well.