Circadian Variation of Myocardial Ischemia in Patients With Unstable Angina Pectoris Secondary to Fixed and/or Spastic Coronary Narrowing

: We investigated the circadian variation of myocardial ischemia in patients with unstable angina using a 24-hour 12-lead electrocardiographic monitoring system with computer analysis. The circadian variation of ischemic attacks in patients who had ST elevation showed a similarity to that of the onset of acute myocardial infarction and most of these patients had vasospasm without organic stenosis; no similarity was seen in patients with organic stenosis.