Systolic anterior motion of the mitral valve masked by general anesthesia.

Systolic anterior motion of the mitral valve is usually associated with hypertrophic obstructive cardiomyopathy that results in left ventricular outflow tract obstruction. This is sometimes treated by volume loading or negative inotropics such as beta blockers. We report a rare case of dynamic systolic anterior motion of the mitral valve, in which a beta blocker did not diminish but anesthetic agents masked intraoperatively. The patient underwent mitral valve replacement, and left ventricular outflow tract obstruction was successfully treated.