Real time three-dimensional transesophageal echocardiography demonstration of membranous septal aneurysm causing severe right ventricular outflow tract obstruction.

In addition to infundibular muscular hypertrophy and anomalous muscle bundles in the right ventricular body, large membranous septal aneurysms (MSA), sinus of valsalva aneurysms, and aneurysms derived from the embryonic venous valve protruding through the tricuspid valve can cause right ventricular outflow obstruction in a patient with ventricular septal defect. Here we describe an adult with a small perimembranous ventricular septal defect complicated by a large MSA causing severe right ventricular outflow obstruction evaluated with real time three dimensional transesophageal echocardiography and cardiac catheterisation. The patient underwent surgical correction of the abnormality and is asymptomatic on follow up.