Preoperative Diagnosis and Surgical Correction of Supravalvular Mitral Stenosis and Ventricular Septal Defect

Abstract

A child with supravalvular mitral stenosis plus ventricular septal defect is reported in whom the correct diagnosis was suspected clinically, confirmed by cardiac catheterization, and successfully treated surgically. Only eight previous cases of supravalvular mitral stenosis have been reported; five of the eight have had associated ventricular septal defects. None was correctly diagnosed before autopsy or surgery. Our patient had a murmur and thrill characteristic of a ventricular septal defect. The pertinent clinical findings suggesting concomitant mitral stenosis consisted of a mitral mid-diastolic murmur that was unusually loud for the magnitude of the left-to-right shunt; a presystolic component to the diastolic murmur; marked left atrial enlargement by x-ray with only moderate pulmonary plethora; and electrocardiographic evidence of left atrial hypertrophy and marked pure right ventricular hypertrophy. Right heart catheterization showed labile passive pulmonary hypertension. Left atrial puncture revealed high proximal and low distal pressure. Surgical correction of both lesions by total cardiac bypass was accomplished through a midline sternal-splitting incision. The supravalvular mitral membrane was excised from the right atrium through an incision in the atrial septum.