Predictive factors of left ventricular ejection fraction improvement after myocardial infarction treated invasively.

Abstract

One indication for the implantation of a cardioverter-defibrillator is a reduction in the left ventricular ejection fraction (LVEF) ≤ 35%. However, in certain patients following an acute myocardial infarction (AMI) a gradual improvement in LVEF has been observed. The factors determining this increase in LVEF have not been conclusively determined. To ascertain the independent predictors associated with the improvement of LVEF in patients following AMI who underwent invasive treatment, while observing their progress over a 6-month follow-up period. Among 665 patients with AMI, a population with LVEF ≤ 35% was selected. After 6 months, a follow-up echocardiogram was performed. Further analysis compared patients with at least 5% improvement in LVEF (Group I) with those without an increase (Group II). Group I consisted of 34 individuals out of 80 patients (43%) with LVEF ≤ 35%. The factors linked to a reduced probability of LVEF improvement were: higher levels of cardiac troponin T (cTnT) (OR 0.841 for 1 ng/ml increase in cTnT, CI 0.715-0.989; p = 0.037), presence of diabetes mellitus (OR = 0.217, 95% CI: 0.058-0.813, p = 0.023) and moderate or severe mitral regurgitation (OR = 0.178, 95% CI: 0.053-0.597; p = 0.005). The study findings indicate that the presence of severe or moderate mitral regurgitation is the most significant factor contributing to the lack of LVEF improvement following AMI. Moreover, the extent of myocardial damage, as indicated by elevated cTnT values, along with compromised adaptation to hypoxia in patients with diabetes, are identified as independent factors associated with reduced chances of an increase in LVEF.