VENTRICULAR SEPTAL DEFECT WITH SHUNT FROM LEFT VENTRICLE TO RIGHT ATRIUM: BACTERIAL ENDOCARDITIS AS A COMPLICATION

Abstract

Intracardiac shunting of blood from left ventricle to right atrium resulting from a defect in the membranous ventricular septum has been observed in 6 patients. The ages ranged from 6 to 17 1/2 years. A thrill and systolic murmur along the lower left sternal border characteristic of a ventricular septal defect, and catheterization data indicating a left-to-right shunt at the level of the right atrium, were present in all. Chest radiography revealed slight to moderate cardiac enlargement and pulmonary vascular engorgement in 5, with specific enlargement of the right atrium in 2. The electrocardiogram was not diagnostic the mean QRS axis was deviated to the left and superiorly in 2. Streptococcus viridans endocarditis was present in 2 and pneumococcal endocarditis strongly suspected in 2 others before operation. Surgical exploration revealed a defect in the tricuspid valve, the thickened margins of which were fused to a defect in the membranous ventricular septum. No vegetations were seen. Closure of the ventricular septal defect before reconstruction of the tricuspid valve provided complete correction in each patient. It is not clear whether the tricuspid defect is acquired secondarily to hemodynamic trauma or whether the trauma is super-imposed on developmentally abnormal tricuspid valve leaflets. In either event hemodynamic trauma predisposes to bacterial infection and the combination enhances fusion of the tricuspid defect to the margins of the ventricular septal defect.