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

Systolic anterior motion of the anterior mitral leaflet (SAM) and concomitant left ventricular outflow obstruction (LVOFO) are commonly seen in hypertrophic cardiomyopathy. However, SAM has also been described together with extensive anteroseptal wall infarction, pericardial exudation and in hypovolemic situations. This report presents two patients examined with M-mode echocardiography which demonstrates that SAM with LVOFO can also occur in association with mitral annulus calcification (MAC). A possible mechanism behind this entity would firstly be the anterior displacement of the mitral ring commonly seen in MAC. Secondly, extension of calcifications to the posterior wall will furthermore impair the LV 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.