Membranous subvalvar pulmonary stenosis in complete transposition; advantage of biplane transoesophageal echocardiography for the diagnosis in a young adult.

A young adult who had previously undergone a Mustard repair for complete transposition developed symptomatic left ventricular outflow tract obstruction. Biplane transoesophageal echocardiography allowed an optimal preoperative assessment. In the longitudinal plane, a discrete calcified membrane was imaged. Consequently, a pulmonary arteriotomy was chosen for the relief of the malformation.