Pulmonic stenosis (PS) is a common congenital heart defect in dogs that is characterized by abnormal development of the pulmonary artery valve (pulmonic valve) on the right side of the heart. This results in an obstruction to blood flow leaving the right ventricle, which cause the right ventricle to hypertrophy (thicken). Treatment recommendations for patients with PS vary based on the severity of PS, type of stenosis (location of the obstructive lesion), and presence or absence of concurrent cardiac defects. The majority of dogs with mild PS have a normal life span and remain asymptomatic. Dogs with severe PS may develop clinical signs such as exercise intolerance, lethargy, syncope (“fainting”), and sudden death, and may have a shortened life expectancy without intervention. Additionally, dogs with severe PS may develop right-sided congestive heart failure (peritoneal effusion [fluid within the abdomen] and/or pleural effusion [fluid in the thoracic cavity surrounding the lungs]), particularly when there is concurrent tricuspid regurgitation.

Balloon valvuloplasty (BVP) has become the accepted method of treatment for the majority of dogs with severe PS. Recent studies have confirmed that dogs with severe PS live longer when BVP is successfully performed. Recommendations for patients with moderate PS are not as clear but should be based on the presence of clinical signs as well as the degree of cardiac remodeling (i.e. right ventricular hypertrophy). BVP is generally a well-tolerated procedure with minimal complications.

Treatment with a beta-blocker (such as atenolol) is often recommended in patients with PS. Beta-blockers are cardioprotective/anti-ischemic by decreasing myocardial oxygen demand (via negative inotropy [decreased contractility] and negative chronotropy [decreased heart rate]). Beta blockade may also help limit arrhythmias (abnormal heart rhythms) secondary to myocardial ischemia and fibrosis. Finally, beta blockade may also help ameliorate secondary dynamic right ventricular outflow tract obstruction.