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The pathophysiology of the onset of morning cardiovascular events
M T Johnstone1, M Mittleman, G Tofler
1Institute for the Prevention of Cardiovascular Disease, Deaconess Hospital, Harvard Medical School, Boston, Massachusetts 02215, USA.
Insights
Daily activities and stress can trigger heart attacks (myocardial infarction) and sudden cardiac death, particularly in the morning. Medications like beta-blockers and aspirin may reduce these risks.
Area of Science:
- Cardiovascular Medicine
- Circadian Biology
- Preventive Cardiology
Background:
- Myocardial infarction (MI) and sudden death are often triggered by daily activities, not random events.
- A morning peak in onset for MI, sudden cardiac death, and stroke suggests a circadian influence.
- Plaque rupture and subsequent thrombus formation are key mechanisms in acute MI.
Purpose of the Study:
- To investigate the role of daily activities and physiological factors in triggering acute cardiovascular events.
- To explore the hypothesis that stress-induced plaque rupture and thrombosis contribute to MI.
- To understand the circadian variation in cardiovascular disease onset for improved prevention strategies.
Main Methods:
- Review of evidence on triggers for myocardial infarction and sudden death.
- Analysis of the temporal relationship between daily activities, stress, and cardiovascular events.
- Examination of the effects of beta-blockers and aspirin on the morning peak of MI onset.
Main Results:
- Evidence suggests daily physical or mental stresses are significant triggers for MI and sudden death.
- A distinct morning peak in the onset of MI, sudden cardiac death, and stroke is observed.
- Beta-blockers and aspirin have demonstrated an ability to reduce the morning peak of acute MI onset.
Conclusions:
- Circadian variations in cardiovascular disease onset highlight vulnerable periods for patients.
- Understanding the mechanisms of plaque vulnerability and rupture is crucial for prevention.
- Pharmacologic protection during vulnerable periods may improve outcomes for patients at risk of cardiovascular events.
Abstract:
Evidence obtained over the past decade indicates that myocardial infarction (MI) and sudden death are not random events but rather, in many cases, may be triggered by the daily activities of the subject. The importance of physical or mental stresses as triggers is suggested by the parallel morning increased onsets of MI, sudden cardiac death, and stroke. Unstable angina and MI are usually precipitated by thrombus formation over a disrupted plaque that causes partial or complete obstruction of coronary artery blood flow. This process may be caused by physiologic factors that lead to rupture of a vulnerable plaque and subsequent thrombosis. Beta-blockers and aspirin, which can diminish these physiologic processes, have been shown to blunt or abolish the morning peak of onset of acute MI. It is hypothesized that occlusive coronary thrombosis occurs when an atherosclerotic plaque becomes vulnerable to rupture, and mental or physical stress causes the plaque to rupture. Increases in coagulability or vasoconstriction triggered by daily activities may also contribute to complete occlusion of the coronary artery lumen. Recognition of the circadian variation of the onset of acute cardiovascular disease suggests the need for pharmacologic protection of patients during the vulnerable periods and provides clues to the mechanism of disease onset, the investigation of which may lead to improved methods of prevention.