Echocardiographic imaging of systolic anterior motion caused by extremely elongated posterior mitral leaflet in hypertrophic cardiomyopathy

Systolic anterior motion is frequently observed in hypertrophic cardiomyopathy (HCM) and causes left ventricular outflow tract (LVOT) obstruction, and systolic anterior motion (SAM) is generally seen at the anterior mitral leaflet (AML) (1). However, an isolated SAM of the posterior mitral leaflet (PML) can be unusually seen. Full coaptation of mitral leaflets and an absence of mitral regurgitation are distinct features of this pattern, and elongation of PML is also essential. We present a case with this unusual pattern to increase awareness about this unique mechanism in HCM.