Eccentric mitral regurgitation jets among patients having sustained inferior wall myocardial infarction

A strong association has been recognized between partial or complete mitral leaflet flail and highly eccentric mitral regurgitation jets. In light of anecdotal observation of eccentric mitral regurgitation apparently due to geometric and functional changes accompanying inferior wall myocardial infarction, the present study was performed to systematically study the eccentricity of mitral regurgitation jets complicating nonacute inferior wall myocardial infarction. Forty-eight consecutive patients with evidence of prior isolated inferior wall myocardial infarction and at least moderate mitral regurgitation but without other valvular, annular, chordal, or ventricular pathology potentially contributory to mitral regurgitation were studied. Mitral regurgitation jets were characterized with respect to eccentricity and anterior versus posterior direction. Regurgitant jet and mitral leaflet position were quantified relative to the mitral annulus. Five of 48 patients (10.4%) had eccentric jets, of which four were directed posterior and one anterior. Although not reaching statistical significance, patients with eccentric jets tended to have somewhat smaller left atrial size (41.2 +/- 7.8 vs 47.2 +/- 9.3 mm, P = 0.17) and left ventricular size (51.5 +/- 3.4 vs 55.1 +/- 7.8 mm, P = 0.13), and higher left ventricular ejection fraction (0.52 +/- 0.11 vs 0.46 +/- 0.09, P = 0.25) compared with patients with noneccentric jets. Leaflet position relative to the mitral annulus was significantly different among patients with eccentric compared with noneccentric posterior jets (54 +/- 10 degrees vs 33 +/- 11 degrees, P = 0.02), implying greater leaflet restriction toward the left ventricular apex. In conclusion, approximately one in 10 patients with isolated inferior wall myocardial infarction and at least moderate mitral regurgitation was found to have marked eccentricity of the regurgitant jet. Leaflet position was more apically displaced among patients with eccentric jets, suggesting greater leaflet restriction in systole. The finding of a highly eccentric posterior mitral regurgitation jet can be due to inferior wall myocardial infarction with posterior leaflet restriction as well as partial or complete anterior mitral leaflet flail.