Right Ventricular Outflow Obstruction Caused by Primary Cardiac Neoplasia

Obstruction to pulmonary blood flow as a result of neoplasia in the right ventricular outflow tract is described in two dogs. Whereas one dog had exertional syncope and a systolic ejection murmur, the other had signs of congestive failure and hypoxia. In both animals the mass was detected in the right ventricle with two-dimensional echocardiography and confirmed angiographically. Although rare, primary right ventricular neoplasia represents a potentially treatable form of cardiac disease and should be considered as a cause of acquired outflow tract obstruction.