Mitral Regurgitation After Anteroapical Myocardial Infarction

Background—Mitral regurgitation (MR) generally accompanies inferobasal myocardial infarction (MI), with leaflet tethering by displaced papillary muscles. Mitral regurgitation is also reported with anteroapical MI without global dilatation or inferior wall motion abnormalities. We hypothesized that anteroapical MI extending to the inferior apex displaces the papillary muscles, tethering the mitral leaflets to cause MR. Methods and Results—In the retrospective part of the study, consecutive anteroapical MI patients were studied. Moderate-severe MR occurred in 9% of 234 patients with only anteroapical MI versus 17% of 242 with inferoapical extension (P<0.001). Ejection fraction was only mildly different (41±4% versus 46±5%; P<0.01). In the human mechanistic portion of the study, 60 anteroapical MI patients (20 with only 2 apical segments involved and 40 with involvement of all 4 apical segments; 20 with MR and 20 without MR) were compared with 20 normal controls. Those with MR (≥moderate) had higher systolic...