A rare case of dynamic left ventricular outflow tract obstruction caused by systolic anterior motion of an abnormal posterior mitral leaflet

Abstract

Dynamic obstruction to left ventricular outflow in patients with hypertrophic cardiomyopathy usually occurs when the anterior mitral leaflet moves forward in systole and approaches or contacts the ventricular septum. This is called as systolic anterior motion (SAM) of anterior mitral leaflet. However, we have recently identified, by M mode and two-dimensional echocardiography a patient with hypertrophic cardiomyopathy who had a unique pattern of mitral valve motion characterized by abnormal mitral valve coaptation and systolic anterior motion of the abnormally elongated posterior mitral leaflet (PML) leading to left ventricular outflow tract obstruction.This was due to intrinsic abnormality of posterior mitral leaflet. Recognition of systolic anterior motion (SAM) of the posterior mitral leaflet (PML) due to intrinsic abnormality may alter the operative approach in selected patients with hypertrophic cardiomyopathy and subaortic obstruction.