[Chronobiological study of ischemic attacks in angina pectoris at rest]

The aims of this study were to determine if the hourly distribution of ischaemic episodes differed as regards ST segment elevation or ST segment depression during ischaemic attacks and differed as regards the degree of coronary atherosclerotic involvement. Twenty-four in-patient drug free subjects with angina at rest underwent ECG continuous Holter monitoring for periods varying from 24 to 168 hours. Four groups of patients were identified: group 1A: 6 patients with ST elevation and 0-1 vessel disease; group 1B: 6 patients with ST elevation and 2-3 vessel disease; group 2A: 3 patients with ST depression and 0-1 vessel disease; group 2B: 9 patients with ST depression and 2-3 vessel disease. During Holter monitoring, 301 ischaemic episodes were registered in group 1A during 576 hours; 173 episodes were registered in group 1B during 624 hours; 41 episodes were registered in group 2B during 528 hours. Using the single and population mean cosinor tests on the episodes of each group, considered as a whole, the following results were found: group 1A showed a circadian rhythm with acrophase at 4:03 a.m. (Fig. 2), group 1B showed a circadian rhythm with acrophase at 10:51 a.m. (Fig. 3), group 2A showed a circadian rhythm with acrophase at 11:15 p.m. (Fig. 5), while group 2B showed ultradian rhythms which lasted 7 and 13 hours (Fig. 6). The chronobiologic analysis of the distribution of the ischaemic attacks confirmed the existence of a circadian rhythm of ischaemic episodes in patients with ST elevation.(ABSTRACT TRUNCATED AT 250 WORDS)