Impact of ischemic time on post-infarction left ventricular function in ST-elevation myocardial infarction treated
Sunanto Ng1, Jan Paul Ottervanger, Arnoud W J van 't Hof
1Isala Klinieken, Department of Cardiology, Zwolle, The Netherlands.
Insights
Ischemic time, the duration from symptom onset to treatment, weakly correlates with left ventricular ejection fraction (LVEF) after ST-elevation myocardial infarction treated with primary PCI. Initial and post-treatment blood flow significantly impacts this relationship.
Area of Science:
- Cardiology
- Interventional Cardiology
- Cardiac Imaging
Background:
- Myocardial necrosis is time-dependent, yet associations between ischemic time and left ventricle function post-infarction remain unclear.
- Previous studies show inconsistent findings regarding ischemic time and left ventricular function after myocardial infarction.
Purpose of the Study:
- To evaluate the association between ischemic time and left ventricular function after ST-elevation myocardial infarction (STEMI) in patients treated with primary percutaneous coronary intervention (PCI).
Main Methods:
- A study of 2529 patients undergoing primary PCI for STEMI.
- Left ventricular ejection fraction (LVEF) measured by radionuclide ventriculography or echocardiography.
- Ischemic time calculated from symptom onset to first balloon inflation.
Main Results:
- A significant but weak negative correlation (r=-0.062, P=0.002) was observed between ischemic time and LVEF.
- LVEF was 45.1±11.7% for ischemic times >6h, 44.6±11.9% for >3-6h, and 43.2±12.2% for ≤3h (P=0.029).
- Initial and post-PCI TIMI flow were linked to longer ischemic times and lower LVEF.
Conclusions:
- Ischemic time is weakly associated with post-infarction LVEF in STEMI patients treated with primary PCI.
- Initial and post-PCI TIMI flow play a crucial role in how ischemic time affects LVEF.
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.
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