The advantage of global strain compared to left ventricular ejection fraction to predict outcome after acute myocardial infarction.

ABSTRACT

The aim of the study was to compare the ability of global strain and left ventricular ejection fraction (LVEF) to predict outcome after acute myocardial infarction (AMI). Left ventricular (LV) function was measured using strain by Doppler and LVEF in 77 patients. Measurements were performed at admission and after 10 ± 5 days. Outcome was measured as the combined end point of cardiac death, reinfarction and hospitalization for heart failure, unstable angina or life threatening arrhythmia. The patients were followed for 3.29 ± 1.59 years (range 0-5.22 years) and 17 cardiac events were registered. The cutoff value of LVEF was 44% for optimal prediction of outcome. We used LVEF ≤ 44% vs. > 44% and the corresponding global strain value ≥ -15.6% vs. < -15.6% to predict cumulative event-free survival. Both methods significantly predicted cardiac combined events at admittance and after 10 days with no difference. After 10 days, however, global strain remained the only significant predictor of outcome in a multivariate logistic regression model (P < 0.0001, odds ratio 1.79). Interobserver reproducibility measured as intraclass correlation was better for global strain than for LVEF (0.92 vs. 0.71). In conclusion, the measurement of global strain in patients with AMI may predict cardiac combined events to the same extent as LVEF in the acute phase and superior to LVEF after 10 days. In addition, global strain demonstrates better interobserver reproducibility and may become an improved bedside tool to evaluate LV function as a prognostic marker after AMI.