Long-term prognostic value of an index of myocardial performance in patients with myocardial infarction.

Abstract

The Tei index of myocardial performance (IMP), which combines parameters of both systolic and diastolic ventricular function, is a useful prognostic factor in many clinical settings. This study assessed the long-term prognostic value of IMP in patients discharged from hospital after acute myocardial infarction (AMI). Doppler/echocardiographic studies were recorded in 90 consecutive patients on Day 14 +/- 2 following an AMI. The IMP was calculated from the Doppler recordings, as a sum of isovolumetric contraction time and isovolumetric relaxation time, divided by the ejection time. The patients were followed for an average (SD) of 57.8 (16.1) months. During this period there were 22 (24%) cardiac events, defined as cardiac deaths (10) or nonfatal recurrent myocardial infarctions (12). After multivariate Cox analysis, Tei index > 0.55 (relative risk [RR] 4.45; 95% confidence interval [CI] 1.28-15.45; p = 0.019), LV end-systolic volume > 65 ml (RR 3.23; 95% CI 1.34-7.79; p = 0.009), and mitral E wave deceleration time < or = 0.145 s (RR 2.94; 95% CI 1.24-6.92; p = 0.014) were the only independent predictors of cardiac events during the follow-up period. In a subgroup of patients with preserved LV systolic function (ejection fraction > 0.40), IMP was the only predictor of cardiac events (RR 6.37; 95% CI 1.32-30.77, p = 0.02). The Tei index of myocardial performance, which is simple and easy to calculate, is a useful tool for risk assessment in patients following myocardial infarction, and in a subgroup of patients with normal or only mildly impaired systolic function.