Mitral Valve Stenosis

Heart valve disease is a condition in which one or more of the heart valves don't work properly. The heart has four valves: the tricuspid, pulmonary, mitral, and aortic valves. These valves have tissue flaps that open and close with each heartbeat. The flaps make sure blood flows in the right direction through the heart's four chambers and to the rest of the body. Mitral valve stenosis is a narrowing of the mitral valve opening caused by abnormalities of the mitral valve. This obstructs blood inflow to the left ventricle. Birth defects, age-related changes, infections, or other conditions can cause one or more of the heart valves to not open fully or to let blood leak back into the heart chambers. This can make the heart work harder and affect its ability to pump blood.

The defect is rare in dogs and is most often seen in the Bulldog, Chihuahua, Great Dane, Keeshond, and Cavalier King Charles Spaniel. It can occur together with other congenital defects such as subaortic stenosis, mitral valve dysplasia, and pulmonic stenosis. Congenital mitral valve stenosis occurs infrequently in dogs often in association with subaortic stenosis. Newfoundlands and Bull Terriers appear predisposed.2 Other large breeds including the German Shepherd Dog, Labrador Retriever, Old English Sheepdog, and Great Dane are also affected.3

Chronic mitral valve disease is associated with increased risk of chronic kidney disease and anemia in dogs. Treatment for medical management of heart failure may play a role in inducing chronic kidney disease.4

Dogs with mitral stenosis may be prescribed diuretics to help eliminate fluid buildup and put on a low-salt diet. Diuretic use needs to be carefully monitored by a veterinarian because it can cause excessive urine output, which may severely reduce blood flow from the heart. Surgery and other treatments are rarely performed because they involve both considerable risk for the animal and high cost.


  1. Cynthia M. Kahn, Scott Line. The Merck/Merial manual for pet health
  2. John K. Dunn. Textbook of small animal medicine
  3. Mike W. S. Martin, Brendan M. Corcoran. Notes on cardiorespiratory diseases of the dog and cat
  4. Preliminary Investigation of Cardiovascular–Renal Disorders in Dogs with Chronic Mitral Valve Disease E. Martinelli,corresponding author 1 , 2 C. Locatelli, 1 S. Bassis, 3 S. Crosara, 2 S. Paltrinieri, 1 P. Scarpa, 1 I. Spalla, 4 AM. Zanaboni, 3 C. Quintavalla, 2 and P. Brambilla 1 J Vet Intern Medv.30(5); Sep-Oct 2016

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