Aneurysm of the membranous septum causing outflow obstruction of the venous ventricle in corrected transposition of the great arteries.

A 58 year-old man with clinical and hemodynamic evidence of subpulmonic stenosis was admitted to our hospital. Angiography revealed corrected transposition of the great arteries and an aneurysm of membranous ventricular septum (AVS) that protruded into the venous outflow tract, causing severe subpulmonic obstruction during systole. The diagnosis was confirmed at surgery, and successful repair of the aneurysm was performed. This was an unusual case because the AVS caused such severe obstruction that the venous ventricular pressure was elevated to a value equal to the systemic level.