systolic anterior motion
Also written as: SAM — systolic anterior motion
Abnormal movement of the mitral valve anterior leaflet toward the ventricular septum during systole, causing outflow tract obstruction.
Full Definition
A pathologic condition where the anterior leaflet of the mitral valve moves toward the interventricular septum during systole, creating left ventricular outflow tract obstruction and mitral regurgitation. SAM is commonly seen in hypertrophic cardiomyopathy but can also occur after mitral valve repair, in hyperdynamic states, or with geometric disturbances of the mitral apparatus. The mechanism involves Venturi forces drawing the leaflet into the outflow tract. Echocardiographic severity is graded based on duration and degree of septal contact. Treatment includes volume loading, beta-blockade, avoiding inotropes, and sometimes surgical intervention to modify the mitral apparatus geometry.
Usage
Usage note: Commonly abbreviated as SAM; specify severity and associated gradient when documenting echocardiographic findings.
In Context
- "Post-repair TEE revealed systolic anterior motion with moderate outflow tract obstruction requiring surgical revision." — Intraoperative report
- "The anesthesiologist treated systolic anterior motion with volume loading and esmolol to reduce contractility." — Anesthesia record