Incidence of very reduced left ventricular ejection fraction during long-term follow-up after acute myocardial infarction: impact for midterm outcomes

Background: For survivors of myocardial infarction (MI), very reduced left ventricular ejection fraction (LVEF) in acute-phase (within hospitalization) occurred about 5% of patients and that was well known as risk factor of cardiac death. Therefore, very reduced LVEF was one of the criteria for Implantable cardioverter defibrillator. However, the very reduced LVEF in chronic-phase were received limited study. Method: We evaluated 2241 consecutive patients with acute MI who received follow-up echocardiography at chronic-phase (after 6-month). Primary outcome was incidence of very reduced LVEF at chronic-phase. Very reduced LVEF was defined LVEF (modified simpson) < 35%. Secondary outcome was cardiac death. Result: During follow up (median 1471 days), very reduced LVEF occurred 9.7% patient. As shown in Kaplan-meier curve, very reduced LVEF occurred 9.3% of patients per 10-year. According to figure, these patients revealed high rate of cardiac death. Even if LVEF at acute-phase exceeded 35%, cardiac death rate of these patients was 9.7%. Conclusions: Very reduced LVEF at chronic-phase occurred 9.3% per 10-year in MI survivors. Regardless of LVEF at acute-phase, very reduced LVEF at chronic-phase associated with cardiac death.