Heart valve dysplasia is a congenital
heart defect which in dogs and cats
affects the aortic, pulmonary, mitral, and tricuspid
Pulmonary valve stenosis and aortic valve stenosis are discussed
separately. Dysplasia of the mitral and tricuspid valves can cause
leakage of blood or stenosis.
Dysplasia of the mitral and tricuspid valves - also known as the
atrioventricular (AV) valves - can appear as thickened, shortened, or notched
valves. The chordae tendinae can be fused or thickened. The papillary muscles
can be enlarged or atrophied. The cause is unknown, but genetics play a big
role. Dogs and cats with tricuspid valve dysplasia often also have an open
foramen ovale, an atrial septal defect, or inflammation of the right atrial
epicardium. In dogs, tricuspid valve dysplasia can be similar to Ebstein's
anomaly in humans.
Mitral valve stenosis is one of the most common congenital heart defects in
The disease and symptoms are similar to progression of valve disease in older
dogs. Valve leakage leads to heart enlargement, arrhythmias, and
congestive heart failure. Heart valve dysplasia can be tolerated for years or
progress to heart failure in the first year of life. Diagnosis is with an
echocardiogram. There is a poor prognosis
with significant heart enlargement.
Abbott, Jonathan A. (2000). Small Animal Cardiology Secrets (1st
ed.). Hanley & Belfus, Inc.
Ettinger, Stephen J.;Feldman, Edward C.(1995).Textbook of Veterinary
Internal Medicine(4th ed.). W.B. Saunders Company.