TRANSIENT ISCHEMIA AFTER ACUTE MYOCARDIAL-INFARCTION - RELATIONSHIP TO EXERCISE ISCHEMIA

To study the implications of transient myocardial ischaemia following acute myocardial infarction we compared ambulatory ST segment monitoring with exercise treadmill testing in 170 patients (mean age 58 years) at 4-8 weeks after admission. Ambulatory monitoring detected transient ischaemia (265 episodes; 249 (94%) silent) in 53/170 patients (31%) which was less frequent than ischaemia during exercise testing (90 patients; 53%) (P<0.0001). However, patients displaying transient ambulatory ischaemia (i) achieved less total exercise (248.7 ± 17.2 vs 318.7±14.1 s; means ± SEM) (P<0.006), (ii) developed exercise ST deviation earlier (172.4 ± 14-3 vs 244.8 ± 16.2 s) (P<0.0004) and (iii) had more widespread exercise ischaemia (3.8 ± 0.3 vs 2.5 + 0.2 ECG leads) (P<0.005). Positive ambulatory ST segment monitoring was infrequently found (12/80 patients; 15%) in the presence of a negative exercise test but did identify the majority of patients (9/11 patients; 82%) with easily provoked exercise ischaemia and hence strongly positive exercise tests. These data suggest a limited role for routine 24 h ambulatory monitoring after myocardial infarction for the diagnosis of ongoing ischaemia but raise the possibility of an important place for this test in prognosis and risk stratification. © 1991 The European Society of Cardiology.