Congenital heart disease in adults: echocardiographic evaluation of left and right ventricular outflow tract obstruction

Abstract

Ventricular outflow tract obstruction commonly occurs as part of complex congenital heart disease syndromes. Outflow tract obstructions of congenital origin are often first diagnosed by echocardiography in adulthood, among patients with no evidence of congenital heart disease in childhood. Such outflow tract obstructions may be of either ventricle, at the valvular, subvalvular, or supravalvular level, and either fixed or dynamic in nature. Echocardiography facilitates both early detection and long term follow-up of these cardiac abnormalities. Advances in echocardiography, such as M-mode echo in the 1970s, 2D echo and color Doppler echo in the 1980s, and transesophageal echocardiography in the past two decades, have made the diagnosis of outflow tract obstruction almost entirely a noninvasive endeavor. Transesophageal echocardiography also has an important role in the operating room when intracardiac tissue is being removed to relieve obstruction. This article describes the pathophysiology of several conditions causing left or right ventricular outflow tract obstruction, with special emphasis on key echo points critical to correct diagnosis and treatment.