Pulmonic stenosis is an abnormal narrowing of the right ventricular outflow tract or stricture of the pulmonary artery. This abnormality leads to the enlargement of the right ventricle of the heart and the increase of the heart blood pressure. Some cases of pulmonic stenosis result from simple fusion of the valve cusps.2 The condition occurs mainly in the English Bulldog, Mastiff, Samoyed, Miniature Schnauzer, West Highland White Terrier, Cocker Spaniel, Beagle, Airedale Terrier, Boykin Spaniel, Fox Terrier, Boxer, Chihuahua, and Scottish Terrier.2
Dogs with pulmonic stenosis may not show clinical signs for many months or years. Signs in severely affected dogs include exercise intolerance, slow growth, labored breathing, accumulation of fluid in the abdomen, a bluish or purplish discoloration of the skin due to lack of oxygenation of the blood, weakness, fainting, collapsing, and sudden death. The most prominent sign of this disease is heart murmur that is discovered during a routine health check. Diagnosis of pulmonic stenosis can be confirmed by echocardiography or cardiac catheterization.1 The blood test may reveal polycythemia.
Treatment involves surgical correction of the stenosis using valvuloplasty procedure. An alternative to surgery, balloon valvuloplasty, is used to decrease pressure in the heart. It is most effective for simple valvular pulmonic stenosis that is not associated with enlargement of the right ventricle. Balloon valvuloplasty is generally attempted before surgical procedures because it is thought to be less risky. The procedure is performed at most cardiology referral centers.1, 2 The prognosis depends on the severity of the stenosis. Animals with mild disease may have a normal life span, but those with severe stenosis often die within three years of diagnosis.2
stenosis - constriction
ventricle - a lower chamber of the heart
right ventricle - the chamber of the heart that receives blood from a corresponding atrium, from which blood is forced into the arteries
polycythemia - an abnormal increase in the number of circulating red blood cells
- Douglas H. Slatter. Textbook of small animal surgery.
- Richard W. Nelson, C. Guillermo Couto. Small Animal Internal Medicine.