What does "systolic anterior motion" of the mitral valve often indicate?

Systolic anterior motion (SAM) of the mitral valve is a phenomenon where the mitral valve moves toward the left ventricular outflow tract during systole. This motion frequently occurs in patients with hypertrophic obstructive cardiomyopathy (HOCM). In HOCM, the hypertrophied interventricular septum can obstruct the outflow of blood from the left ventricle, especially in the presence of certain conditions such as increased contractility or decreased preload. As the left ventricle contracts, the anterior leaflet of the mitral valve can be pulled towards the septum, resulting in SAM.

In HOCM, this mechanism leads to functional obstruction, and identifying this movement during echocardiography is crucial as it can provide insight into the severity of the obstruction and direct management decisions. Recognizing SAM is an important part of diagnosing and managing patients with HOCM.