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Circadian variation of cardiovascular disease and sympathetic activity
J E Muller1, G H Tofler, S N Willich
1Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
Insights
Chronic coronary artery disease events, including myocardial infarction and sudden cardiac death, peak in the morning and evening. This circadian rhythm, linked to platelet activity, may inform new prevention strategies.
Area of Science:
- Cardiology
- Circadian Biology
- Thrombosis Research
Background:
- The transition from chronic coronary artery disease to acute events like myocardial infarction or sudden cardiac death remains incompletely understood.
- Understanding the temporal patterns of these acute cardiovascular events is crucial for developing effective preventive measures.
Purpose of the Study:
- To investigate the time-of-day patterns for the onset of nonfatal myocardial infarction and sudden cardiac death.
- To explore potential mechanisms, such as platelet aggregability, underlying these temporal patterns.
Main Methods:
- Analysis of the onset times for 703 cases of nonfatal myocardial infarction, objectively assessed by creatine kinase-MB levels.
- Examination of death certificates for 2,203 cases of sudden cardiac death to determine event timing.
- Correlation of event timing with daily variations in platelet aggregability.
Main Results:
- Both nonfatal myocardial infarction and sudden cardiac death exhibited significant circadian rhythms, with peaks occurring in the morning and a secondary peak in the evening.
- Platelet aggregability demonstrated an increase during morning hours, coinciding with the primary peak in cardiovascular events.
- A temporal association was observed between increased platelet activity and the incidence of acute coronary events.
Conclusions:
- The study suggests that circadian variations in physiological factors, particularly platelet activity, play a role in the pathogenesis of myocardial infarction and sudden cardiac death.
- These findings provide a potential mechanistic link for the observed morning peak in acute cardiovascular events.
- Identifying these time-of-day patterns may pave the way for novel, chronotherapy-based prevention strategies for coronary artery disease.
Abstract:
The events that convert chronic coronary artery disease to acute myocardial infarction or sudden cardiac death are poorly understood. We studied the time of day of onset of nonfatal myocardial infarction (as judged objectively by CK-MB values, n = 703) and sudden cardiac death (as judged by death certificates, n = 2,203) to determine if there was an increased incidence associated with a particular time of day. Both conditions were found to have prominent circadian rhythms with a primary peak in the morning and a secondary peak in the evening. Platelet aggregability, which has been proposed as a component of myocardial infarction and sudden cardiac death, was also found to increase during the morning. These findings suggest a mechanism for myocardial infarction and sudden cardiac death and may lead to improved methods of prevention.