Mitral Annulus Calcification, Systolic Anterior Motion of the Anterior Mitral Leaflet and Outflow Obstruction in Two Patients without Hypertrophic Cardiomyopathy

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Abstract
Systolic anterior motion of the anterior mitral leaflet (SAM) and concomitant left ventricular outflow obstruction (LVOFO) were commonly seen in hypertrophic cardiomyopathy. SAM was also described together with extensive anteroseptal wall infarction, pericardial exudation and in hypovolemic situations. Two patients examined with M-mode echocardiography are presented. SAM with LVOFO can also occur in association with mitral annulus calcification (MAC). A possible mechanism behind this entity would be the anterior displacement of the mitral ring commonly seen in MAC. Extension of calcifications to the posterior wall will impair the LV [left ventricular] contraction leading to loosely stretched chordae tendineae during systole and hence a motion of the anterior mitral valve along the blood stream (SAM) leading to LVOFO.