Evolution of left ventricular ejection fraction and its relationship to infarct size after acute myocardial infarction.

OBJECTIVES

The aim of this study was to investigate the evolution of left ventricular (LV) function and infarct size in patients with acute myocardial infarction (MI) treated with primary coronary stenting.

BACKGROUND

Little evidence exists on the relationship between LV function and evolution of infarct size after MI.

METHODS

This study included 626 patients with first acute MI who underwent 2 angiographic and 3 scintigraphic examinations within 6 months after the acute event. Angiographic left ventricular ejection fraction (LVEF) at baseline and at 6-month angiography, and perfusion defects before intervention and at 7- to 14-day and 6-month scintigraphy after intervention were measured. An analysis of 3-year follow-up was performed.

RESULTS

Scintigraphic perfusion defect (median [25th, 75th percentiles]) was 24.6% [14.0%, 41.0%] of LV before intervention; it was reduced to 11.0% [5.0%, 24.0%] of LV at 7 to 14 days and further to 8.0% [2.0%, 19.0%] of LV at 6 months (p < 0.001). The LVEF was 51.6 +/- 12.0% before intervention and increased to 57.4 +/- 12.8% at 6 months (p > 0.001). Independent predictors of LVEF change were baseline LVEF (p < 0.001), initial perfusion defect (p < 0.001), early reduction in perfusion defect (p < 0.001), late reduction in perfusion defect (p < 0.001), peak creatine kinase-MB (p < 0.001), and smoking (p = 0.05). Three-year mortality was 1.2% in patients with improved LF function versus 5.6% in patients with worsened LV function (relative risk 0.29, 95% confidence interval 0.09 to 0.90; p = 0.03).

CONCLUSION

Patients with acute MI show an improvement in LV function and a reduction in infarct size within 6 months after coronary reperfusion. This improvement is associated with better long-term survival.