Circadian Variability and Its Influence on Infarct Size and Clinical Outcome Among Japanese Patients With Acute...

Area of Science:

• Cardiology
• Chronobiology
• Clinical Research

Background:

• Significant circadian variation exists in myocardial infarction (MI) onset, with a peak in the early morning.
• The influence of this circadian rhythm on post-acute myocardial infarction (AMI) clinical outcomes and infarct size remains unclear.

Purpose of the Study:

• To investigate whether circadian variation affects infarct size and clinical outcomes in patients with ST-elevation myocardial infarction (STEMI).

Main Methods:

• The study analyzed 2,251 patients with STEMI from the Japan AMI Registry (JAMIR).
• Patients were stratified into four time periods based on the documented time of MI onset.
• Peak creatine kinase (CK) levels were used as the primary indicator of infarct size, with in-hospital mortality and 1-year clinical outcomes as secondary endpoints.

Main Results:

• No significant differences in peak CK levels (indicating infarct size) were observed among the four time period groups.
• The time of MI onset did not significantly correlate with peak CK levels.
• Secondary endpoints, including in-hospital mortality, 1-year all-cause mortality, recurrent MI, stroke, stent thrombosis, and a composite endpoint, showed no significant differences across the time period groups.

Conclusions:

• Circadian variation does not appear to influence infarct size or clinical outcomes in patients experiencing STEMI.