Obstruction of the left ventricular outflow tract caused by bicuspid aortic valve and discrete subaortic membrane

Bicuspid aortic valve is the most common congenital cardiac anomaly and it may often coexist with other congenital cardiac anomalies. Its coexistence with discrete subaortic membrane, causing obstruction of the left ventricular outflow tract is very rare. A 21-year-old male patient presented with complaints of exertional dyspnea and dizziness. On transthoracic echocardiography, the parasternal short-axis view showed a bicuspid aortic valve, and parasternal long-axis color Doppler view showed a mosaic pattern in the subaortic region. A more careful examination of the parasternal long-axis views revealed a discrete subaortic membrane. Continuous-wave Doppler flow velocity obtained from the aortic valve was normal; however, a peak gradient of 30 mmHg was observed with the Valsalva maneuver. The fact that there are very few reports on this rare coexistence may be due to failure to recognize discrete subaortic membrane during echocardiographic examination.