title: Circadian variations in myocardial ischemia. Implications for management.
abstract: Extended ambulatory electrocardiographic monitoring in the patient's customary environment provides clear evidence of circadian patterns in myocardial ischemic episodes. In patients with effort angina, the highest activity occurs between 6 AM and noon. This coincides with peaks in diurnal variation of frequency of acute myocardial infarction, stroke, and sudden death. A number of potential underlying common triggering mechanisms, including catecholamine secretion, sympathetic nervous system activity, blood pressure, heart rate, cortisol secretion, and aggregability of platelets, exhibit similar surges. As a result of these coinciding morning peaks, myocardial oxygen demand is increased and oxygen supply reduced after a person arises in the morning. Attention to this vulnerable period is merited in the timing and choice of medication, both to prevent or reduce ischemia and to modify potential disease-triggering mechanisms.
authors.affiliation: Veterans Affairs Medical Center, Gainesville, FL.
authors.forename: C J
authors.initials: CJ
authors.lastname: Pepine
mesh_terms: D002940:Circadian Rhythm / Q000187:drug effects; D002985:Clinical Protocols; D003327:Coronary Disease / Q000188:drug therapy / Q000503:physiopathology*; D015716:Electrocardiography, Ambulatory; D006801:Humans; D010101:Oxygen Consumption