Mitral valve and papillary muscle abnormalities in hypertrophic obstructive cardiomyopathy

Purpose of review This section reviews abnormalities of the mitral valve apparatus that are associated with hypertrophic obstructive cardiomyopathy. Recent findings Mitral valve abnormalities in hypertrophic obstructive cardiomyopathy include leaflet elongation and thickening and hypertrophy with anterior displacement of the papillary muscles. This combination contributes to the development of systolic anterior motion. The resultant flow forces during systolic anterior motion pulling the leaflets into the left ventricular outflow tract also result in reduced leaflet coaptation and a posteriorly directed mitral regurgitant jet. Additional mitral valve abnormalities include degenerative leaflet changes, aberrant chordal attachments and papillary muscle anomalies. Summary Mitral valve abnormalities are common in hypertrophic obstructive cardiomyopathy and play an important role in the pathophysiology of dynamic left ventricular outflow tract obstruction.