The association of fixed and dynamic left ventricular outflow obstruction

Twelve patients were investigated echocardiographically and angiographically and were shown to have severe fixed obstruction to the left ventricular outflow tract. Eight had valvular stenosis, and four had discrete subvalvular membranes. Two of the patients had additional dynamic obstruction of the left ventricular outflow tract. This was recognized preoperatively by echocardiography because of abnormal systolic motion of the mitral leaflet. At the time of definitive surgery for relief of the fixed obstruction, the additional dynamic obstruction was identified and treated, since persistent residual obstruction may lead to death in the immediate postoperative period or to long-term symptoms. The dynamic left ventricular outflow obstruction is probably a result of the hypertrophy produced by the fixed obstruction.