[Silent myocardial ischemia in long-term ECG with various mani festations of coronary heart disease].

Silent myocardial ischaemia seems to be of prognostic value in coronary artery disease. We examined 47 patients with coronary artery disease: 1. 20 patients with a history of myocardial infarction (MI), 2. 15 patients with chronic stable angina pectoris without a history of myocardial infarction (sAP), and 3. twelve patients with unstable angina with or without a history of myocardial infarction (uAP). Horizontal and downsloping ST-segment-depressions greater than or equal to 1 min and greater than or equal to 0.1 mV were defined as significant. There were 132 ST-segment-depressions, the relation between symptomatic and asymptomatic being 1:7.3, in MI 1:6.2, in sAP 1:5.3, in uAP 1:14. Heart rate increased before beginning of ST-segment-depression in 74% in MI, in 86% in sAP, but only in 38% in uAP. In sAP ST-segment-depressions were smaller (14% greater than 0.2 mV, none greater than 0.3 mV) than in patients with MI (42% greater than 0.2 mV, 12% greater than 0.3 mV) and uAP (25% greater than 0.2 mV, 9% greater than 0.3 mV). Mean duration of ST-segment-depression was 15.3 +/- 11.7 min in sAP (2 to 49 min), 28.5 +/- 35.6 min in MI (2 to 168 min), and 41.2 +/- 40 min in iAP (2 to 140 min). ST-segment-depressions in MI and sAP showed a circadian rhythm with a peak at midday and in the early evening and a small amount of ST-segment-depressions at night. In uAP ST-segment-depressions did not show that circadian variation. The number of ST-segment-depressions was higher in uAP than in MI and sAP.(ABSTRACT TRUNCATED AT 250 WORDS)