What is SAM in the heart?

What is SAM in the heart?

SAM is short form for systolic anterior motion. It is a peculiar movement of anterior mitral leaflet seen in hypertrophic obstructive cardiomyopathy, a heart muscle disease in which the left ventricle gets grossly thickened. Normally the anterior mitral leaflet moves posteriorly during systole closing the mitral orifice. But in SAM, it is an abnormal anterior movement of the anterior mitral leaflet. SAM causes narrowing of left ventricular outflow tract which is anterior to the anterior mitral leaflet. SAM also prevents proper apposition of the mitral leaflets producing mitral regurgitation. A plaque may also form in the region of LVOT where there is SAM septal contact. This can act as nidus for endocarditis occasionally.