Incomplete atrioventricular septal defect with hypoplastic left ventricle and left atrioventricular valve stenosis.

A 2-month-old male infant with incomplete atrioventricular septal defect associated with a hypoplastic left ventricle and left atrioventricular valve stenosis successfully underwent biventricular repair. Echocardiography showed marked dilatation in the right ventricle and a diminutive left ventricle. However, the left ventricular chamber occupied the apex. Left atrioventricular valve stenosis was due to a solitary papillary muscle. Cardiac catheterization showed pulmonary/systemic flow ratio of 3.61, left ventricular end-diastolic volume of 63% of normal, and right ventricular end-diastolic volume of 324% of normal. During surgical repair, the solitary papillary muscle was divided longitudinally and the ostium primum was closed with a bovine pericardium. Postoperative left ventricular function was appropriate. Even when the preoperative end-diastolic left ventricular volume is small, if the left ventricle chamber is at the apex, then the left ventricular performance can be expected to be appropriate to tolerate the volume load after ostium primum closure.