European survey on circadian variation of angina pectoris (ESCVA): design and preliminary results.

A circadian variation has been observed for acute coronary syndromes (myocardial infarction, sudden cardiac death, angina pectoris) with a peak during the morning and a trough during the night. The previous reports, however, were based primarily on selected patients in clinical studies. The present study has been designed to determine the timing of attacks of angina pectoris in ambulatory patients, the association of wake time and possible external triggers with angina attacks, and the influence of cardiac medication. The European Survey on Circadian Variation of Angina Pectoris is a multicenter international cross-sectional survey of outpatients treated in general medical practice of seven European countries. Inclusion criteria are stable angina pectoris for at least 3 months, average frequency of two or more attacks per week, and treatment with on-demand nitrates. Standardised self-administered questionnaires are provided to all consecutive patients and their physicians. From January to July 1998, 1087 patients (61% male, 64 +/- 9 years; 39% female, 67 +/- 10 years) were enrolled in 196 centers. A total of 3453 angina pectoris attacks were reported, on average 3.2 per patient per week (range 0-48). The occurrence of angina pectoris attacks demonstrates a significant circadian variation (p < 0.001) with a primary morning peak from 9:00 to 12:00 (relative risk 3.0 compared with other times of day) and a secondary afternoon peak from 15:00 to 18:00. Of all attacks, 50% occured within 6 h after awakening. Seventy-four percent of all patients reported possible external triggers of angina such as physical activity or anger. The present multicenter survey in general medical practice demonstrates a marked wake time related circadian variation in angina pectoris attacks. To improve preventive strategies, therefore, type, dosage and particularly timing of cardiac medication appear of importance, as may be behavior modification approaches.