Impact of ischemic time on post-infarction left ventricular function in ST-elevation myocardial infarction treated with primary percutaneous coronary intervention

Abstract

Background: Myocardial necrosis is a time-dependent event. Nevertheless, clinical studies on association between ischemic time and left ventricle function showed inconsistent findings. Aim of current study is to evaluate the association between ischemic time and the post-infarction left ventricular function in ST-elevation myocardial infarction treated with primary PCI.

Methods: In 2529 patients treated with primary PCI, left ventricular ejection fraction (LVEF) was measured before discharge (median day 4) by radionuclide ventriculography or by echocardiography if patients had atrial fibrillation. Ischemic time was calculated from symptom onset to first balloon inflation.

Results: The correlation between ischemic time as continuous variable and LVEF was significant but weak (P=0.002, r=-0.062). The LVEF of patients in ischemic time intervals of >6, >3-6, and ≤3 h was 45.1±11.7%, 44.6±11.9%, and 43.2±12.2%, respectively (P=0.029). Adjusted odds ratio of the ischemic time intervals for LVEF<40% was 1.14 (95% CI 1.00-1.30). TIMI flow 0 before and TIMI flow 3 after PCI were related with both longer ischemic time and low LVEF.

Conclusion: Ischemic time was associated with post infarction LVEF in patients treated with primary PCI, although this association was weak. Initial TIMI flow and post-PCI TIMI flow played important role in impact of the ischemic time on the LVEF.