Pulmonic Stenosis in a Bulldog
History: The dog was diagnosed with pulmonic stenosis by the cardiologist.
Gross lesions: The right ventricular myocardium was severely thickened to about 7-10 times the normal width. The pulmonic outflow tract was markedly narrowed, and the pulmonary artery was dilated and had a very thin wall.
A common cause of pulmonic stenosis in English Bulldogs results from a single right coronary artery which gives off a branch which encircles the pulomary artery causing a constriction. This is called a “circumpulmonary left coronary artery”.
Other causes of pulmonic stenosis in dogs is valvular stenosis, which is very common, and is caused by malformed pulmonic valves. The valve develops abnormally in utero and becomes dome shaped with a central perforation. The valve is unable to open properly during systole and causes occlusion of the outflow tract.
Another cause of PS is subvalvular stenosis, which is caused by a ring of fibrous tissue below the pulmonic valve, which constricts the outflow tract.
Gross lesions of pulmonic stenosis include: Right ventricular hypertrophy, post-stenotic dilatation of the pulmonary artery. Pulmonic stenosis is inherited in Beagles and suspected to be inherited in English Bulldogs, Bull Mastiffs, Chihuahuas, and terriers.