Circadian variation of oxidant stress in myocardial ischaemic syndromes

Abstract

Circadian variation of onset of acute myocardial infarction and anginal episodes have been noted with a peak occurring in the morning hours [ 1 Gilpin E.A. Hjalmarson A. Ross Jr., J. Subgroups of patients with atypical circadian patterns of symptom onset in acute myocardial infarction. Am. J. Cardiol. 1990; 66: 7G-11G Google Scholar , 2 Willich S.N. Linderer T. Wegscheider K. et al. Increasing morning incidence of myocardial infarction in ISAM study: absence with prior beta-adrenergic blockade ISAM study group. Circulation. 1989; 80: 853-858 Google Scholar ]. Factors affecting circadian variation in cardiovascular disorders include heart rate, catecholamine release, platelet aggregation and release of exogenous factors [ [3] Cafagna D. Potente E. Circadian patterns of ischaemic events. Minnerva Med. 1996; 87: 455-464 Google Scholar ]. The haemodynamic and prothrombic factors cause development of acute myocardial ischaemic syndromes. Oxy free radicals are believed to be involved in atherothrombosis [ 4 Bolli R. Jeroudi M.O. et al. Direct evidence that oxygen derived free radicals contribute to post ischaemic myocardial dysfunction in the infarcted dog. Proc. Natl. Acad. Sci. USA. 1989; 66: 4695-4699 Google Scholar , 5 Kuzuya T. Hoshida S. et al. Detection of oxygen derived free radical generation in the canine post ischaemic heart during late phase of reperfusion. Circ Res. 1990; 66: 1160-1165 Google Scholar ]. The circadian variation in the oxidant stress status in myocardial ischaemia is of interest to design optimal timing of drug regimen.