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Updated: Jan 24, 2026
Postconditioning with Lactate-enriched Blood for Cardioprotection in ST-segment Elevation Myocardial Infarction
Published on: May 28, 2019
Time-of-day at symptom onset was not associated with infarct size and long-term prognosis in patients with ST-segment
Hendrik B Sager1,2, Oliver Husser3,4, Sabine Steffens5,6
1Klinik für Herz- und Kreislauferkrankungen, Deutsches Herzzentrum München, Technische Universität München, Lazarettstr. 36, 80636, Munich, Germany. hendrik.sager@tum.de.
Insights
The time of day when ST-segment elevation myocardial infarction (STEMI) symptoms begin does not impact heart attack size or long-term survival. This finding applies to patients treated with primary percutaneous coronary intervention (PPCI).
Area of Science:
- Cardiology
- Circadian Biology
- Medical Prognostics
Background:
- ST-segment elevation myocardial infarction (STEMI) exhibits circadian variation, with peak incidence in morning hours.
- Existing data on the impact of symptom onset time on infarct size and long-term prognosis in STEMI patients are conflicting.
- The study investigates the relationship between the time of day of STEMI symptom onset and infarct size or long-term mortality in patients undergoing primary percutaneous coronary intervention (PPCI).
Purpose of the Study:
- To determine if the time of day of STEMI symptom onset influences final infarct size.
- To assess the association between STEMI symptom onset time and 5-year all-cause mortality.
- To evaluate the effect of symptom onset time on left ventricular ejection fraction recovery post-PPCI.
Main Methods:
- A cohort of 1206 STEMI patients undergoing PPCI was analyzed.
- Single photon emission computed tomography (SPECT) imaging was performed before and 7-14 days after PPCI to assess infarct size.
- Time of STEMI symptom onset was categorized into 6-hour intervals, with co-primary endpoints of infarct size at 10 days and 5-year all-cause mortality.
Main Results:
- No significant difference in median infarct size was observed across different 6-hour symptom onset intervals (p=0.87).
- Kaplan-Meier estimates showed no significant difference in 5-year all-cause mortality based on symptom onset time (log-rank test p=0.30).
- Adjusted analyses revealed no association between time of day and infarct size (p≥0.76) or 5-year mortality (p≥0.25). Left ventricular ejection fraction recovery at 6 months was also not associated with symptom onset time.
Conclusions:
- Time of day of symptom onset in STEMI patients undergoing PPCI is not associated with scintigraphic infarct size.
- STEMI symptom onset time does not correlate with left ventricular ejection fraction recovery at 6 months post-PPCI.
- The time of day of STEMI symptom onset does not predict 5-year all-cause mortality in patients treated with PPCI.
Background:
ST-segment elevation myocardial infarction (STEMI) displays circadian variability with the highest incidence in the morning hours. Data on whether the time-of-day at symptom onset affects infarct size or patients' long-term prognosis are conflicting. We sought to investigate the association of time-of-day at symptom onset with infarct size or long-term mortality in patients with STEMI undergoing primary percutaneous coronary intervention (PPCI).
Methods:
This study included 1206 STEMI patients undergoing PPCI. All patients underwent single photon emission computed tomography (SPECT) imaging with 99mTc-sestamibi before and 7-14 days after PPCI. The co-primary endpoints were final infarct size on day 10 after STEMI and all-cause mortality at 5-year follow-up. Time-of-day at symptom onset of STEMI was categorized in 6-h intervals.
Results:
In patients presenting from 0 to 6 h, 6 to 12 h, 12 to 18 h, and 18 to 24 h, the infarct sizes (median [25th-75th percentiles]) were 10.0 [3.0-24.7], 10.0 [3.0-24.0], 10.0 [3.0-22.0], and 9.0 [3.0-21.0] of the left ventricle, respectively (p = 0.87); the Kaplan-Meier estimates of 5-year all-cause mortality were 13.6%, 8.7%, 13.7% and 9.3%, respectively (log-rank test p = 0.30). After adjustment, time-of-day was not associated with infarct size (p ≥ 0.76 for comparisons with infarct size from reference [6-12 h] time interval) or 5-year all-cause mortality (p ≥ 0.25 for comparisons with mortality from reference [6-12 h] time interval). Time-of-day at symptom onset of STEMI was not associated with differences in the recovery of left ventricular ejection fraction 6 months after STEMI.
Conclusions:
In patients with STEMI undergoing PPCI, time-of-day at symptom onset was neither associated with scintigraphic infarct size, left ventricular ejection fraction recovery at 6 months nor with 5-year mortality.
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