Severity of silent myocardial ischemia on ambulatory electrocardiographic monitoring in patients with stable angina pectoris: relation to prognostic determinants during exercise stress testing and coronary angiography.

The relation of silent ischemia in patients with stable angina to known predictors of severity of coronary disease on exercise stress testing and coronary angiography is poorly defined. This issue was therefore examined with use of Holter electrocardiographic (ECG) recordings, treadmill exercise tests and angiographic indexes in 102 patients (not taking antianginal therapy) and the results were compared with Holter and treadmill findings in 42 volunteers. A total of 159 ischemic episodes (90% silent) were identified during 2,503 h on Holter recording in 97 patients (mean duration per episode 22.7 +/- 147 min; range 1 to 234). Holter recordings had a 92% specificity and an 80% positive predictive value, but a sensitivity of only 37% and a negative predictive value of 27% for coronary disease. Sixty-three patients (Group I) had no ischemia on Holter recording, 22 (Group II) had a cumulative duration of 1 to 60 min/24 h and in 12 (Group III) ischemia exceeded 60 min/24 h. There was no significant correlation between cumulative ischemia duration on Holter recording and exercise duration or time to ST segment depression on treadmill exercise. In general, the greater the number of coronary vessels involved and the higher the proximal coronary artery stenosis score, the greater the likelihood of ischemia and the longer the cumulative ischemia duration on Holter recording. Irrespective of the severity of coronary disease, in about 25% of Holter recordings in each angiographic category there were no ischemic episodes.(ABSTRACT TRUNCATED AT 250 WORDS)