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[Circadian changes of myocardial infarction]
1Unité de pharmacologie clinique, hôpital Bellevue, Saint-Etienne.
Archives Des Maladies Du Coeur Et Des Vaisseaux
|June 1, 1993
Summary
Myocardial infarction (MI) shows a morning peak, occurring 1.5-2 times more frequently between 8-12 AM. Medications like aspirin and betablockers can reduce this morning MI risk.
Area of Science:
- Cardiology
- Chronobiology
Background:
- Circadian rhythms influence the timing of acute cardiovascular events.
- Myocardial infarction (MI) onset exhibits a distinct circadian pattern, with a notable morning peak.
Purpose of the Study:
- To investigate the circadian rhythm of myocardial infarction onset.
- To explore factors influencing the morning peak and the effect of medications.
Main Methods:
- Review of existing studies on myocardial infarction timing.
- Analysis of population characteristics and medication effects (calcium antagonists, aspirin, betablockers).
Main Results:
- A peak in MI onset occurs between 8-12 AM, 1.5-2 times higher than other times.
- This pattern is consistent across populations but less pronounced in younger individuals.
- Betablocker and aspirin therapy decrease morning MI frequency, while calcium antagonists do not.
Conclusions:
- Circadian variations in physiological factors like coagulation, platelet aggregation, and catecholamine levels may underlie the morning MI peak.
- Waking and rising times are implicated in the morning surge.
- Betablocker therapy, by suppressing this peak, suggests a role for catecholamines; optimal dosing for morning efficacy is recommended.