A rare case of isolated congenital right ventricular inflow obstruction due to the presence of an intraventricular muscular shelf.

A 56-year-old man presented with anasarca and a 40-lb weight gain that had occurred over the course of 3 to 4 weeks. He had a history of permanent atrial fibrillation and a congenital anomaly of the right ventricular inflow tract. This defect consisted of a muscular shelf in the right ventricular inflow tract, which encased the tricuspid subvalvular apparatus in such a manner that it created tricuspid stenosis. The clinical consequences of this anatomic and hemodynamic situation were a massively dilated right atrium, permanent atrial fibrillation, and clinical evidence of right-sided heart failure, including fluid retention and ascites. The patient underwent surgical resection of the muscular shelf, which was followed by progressive resolution of the ascites and fluid retention.