EXCISION OF THE SEPTAL LEAFLET OF THE ATRIOVENTRICULAR TRICUSPID VALVE: AN EXPERIMENTAL STUDY.

SUMMARY The anatomy and function of the atrioventricular tricuspid valve were studied in the canine heart. The tricuspid valve functioned as a bicuspid valve, the septal leaflet acting as a baffle for the synchronously functioning anterior and posterior cusps. Excision of the septal leaflet in 16 dogs restudied at 4 to 5 months produced a harsh, pansystolic murmur over the precordium. Phonocardiography demonstrated a systolic murmur in the right ventricle and no murmur in the right atrium. There were no hemodynamic changes as a result of the slight regurgitation demonstrated by angiocardiography. The clinical application will be the subject of another communication.