RELATION OF LEFT-VENTRICULAR CHAMBER SHAPE IN PATIENTS WITH LOW (LESS-THAN-OR-EQUAL-TO-40-PERCENT) EJECTION FRACTION TO SEVERITY OF FUNCTIONAL MITRAL REGURGITATION

Functional mitral regurgitation (MR) often develops in patients with heart failure, and when severe can play a major role in reducing effective left ventricular (LV) stroke output and contribute to worsening of heart failure. Recent studies in patients with severe heart failure and in animal models of experimental heart failure have demonstrated that change in LV shape, namely increased LV chamber sphericity, is a primary factor in the etiology of functional MR.(1-3) However, it is unclear whether the severity of functional MR, once MR is established, is also dictated, in large part, by the degree of LV chamber sphericity. It has been suggested that other components of LV remodeling, including LV chamber enlargement and mitral annular dilatation, could also potentially contribute to the severity of functional MR.(3,4) In the present study, we tested the hypothesis that the degree of LV chamber sphericity rather than mitral annular dilatation or LV size is the primary factor influencing the severity of functional MR in patients with low ejection fraction.