Functional ischemic mitral regurgitation in acute myocardial infarction: Importance of changes in left ventricular shape and regional function

Abstract

Functional ischemic mitral regurgitation (IMR) is common in patients with ischemic left ventricular dysfunction after myocardial infarction, and significantly worsens prognosis. The aim of this study is to determine the relative importance of the global and regional left ventricular (LV) remodelling in the occurrence of IMR. Eighty-one patients (mean age = 61 ± 11 years) admitted with acute myocardial infarction (AMI) were screened. Patients with atrial fibrillation and organic valvular diseases were excluded from the study. Echocardiography (two-dimensional and Doppler echocardiograms) was performed in the first week after admission. The 81 patients were divided in 2 groups: with IMR (group1 = 39 patients) and without IMR (group2 = 42 patients). LV volumes were calculated by apical biplane Simpson's rule. The LV wall-motion score (WMS) index was obtained in a 17-segment model according to established methods. To identify the influence of regional wall-motion impairment for each individual LV segment, the mean WMS was calculated for each segment and compared between the 2 groups. The echocardiographic parameters that were associated with IMR were: LV dilatation and sphericity ( P < 0.0001), reduced ejection fraction ( P < 0.0001), inferior ( P < 0.001) inferolateral ( P = 0.01) and anterolateral ( P = 0.02) asynergy. The results of this study indicate the importance of abnormalities of both LV geometry and regional wall motion in the pathogenesis of IMR after myocardial infarction. Clinically, these findings imply that myocardial salvage by early coronary revascularisation may improve outcome by preserving LV function and decreasing the incidence of IMR.