Aneurysm of the membranous ventricular septum producing subpulmonic outflow tract obstruction.

The authors report the case of a 31-year-old asymptomatic male who, following investigations for cardiac murmur, was found to have congenitally corrected (status solitus of the atria, left looping of the ventricles, leftward aorta in relation to the pulmonary artery [S,L,L]) transposition of the great vessels with significant right-sided ventricular outflow tract obstruction due to a large aneurysm of the membranous ventricular septum. Diagnosis was made with transesophageal echocardiography and confirmed during corrective surgery. The authors review the literature with regard to aneurysms of the membranous ventricular septum and their association with congenital heart disease, and they discuss the use of noninvasive tests aiding the diagnosis.