PROGNOSTIC VALUE OF EXERCISE STRESS-TESTING VERSUS AMBULATORY ELECTROCARDIOGRAPHY AFTER ACUTE MYOCARDIAL-INFARCTION - A 3 YEAR FOLLOW-UP-STUDY

Background: The aim of this study was to evaluate the prognostic signi ficance of myocardial ischemia detected by ambulatory ECG monitoring ( AEM) and exercise stress testing (ExT) following acute myocardial infa rction. Methods: The prognostic value of AEM versus ExT was studied pr ospectively in 74 patients with a recent acute myocardial infarction. Myocardial ischemia was diagnosed by the presence of ST-segment depres sion occurring during AEM or ExT 4+/-2 and 7+/-4 days after hospital a dmission respectively. ST-segment depression during AEM was defined as a horizontal/downsloping depression of greater than or equal to 0.1 m V from the reference baseline, measured 80 ms after the J point, elaps ing greater than or equal to 1 min. ST-segment depression at ExT was d etermined as greater than or equal to 1 mm horizontal or downsloping S T-segment depression in at least two consecutive ECG leads. Results: T wenty-two patients (30%) showed ST-segment depression during AEM and 3 4 (49%) on ExT. During a mean follow-up period of 3 years (36+/-15 mon ths), 10 patients (45%) with ST-segment depression on AEM died compare d with eight (15%) without; 12 patients (35%) with ST-segment depressi on on ExT died versus three (8%) without. Death or reinfarction occurr ed in 13 patients (59%) with ST-segment depression on AEM versus nine (17%) without, and in 13 patients (38%) with ST-segment depression on ExT compared with six (17%) without. Revascularization procedures were similar in patients with or without ST-segment depression during AEM and ExT. Cardiac events, defined as death, nonfatal reinfarction or re vascularization, occurred in 18 patients (82%) with ST-segment depress ion on AEM versus 20 (38%) without, and in 23 patients (68%) with ST-s egment depression on ExT versus 11 (31%) without. Survival analysis us ing Kaplan-Meier curves showed that patients showing no ST-segment dep ression with either technique had longer survival times than did patie nts showing ST-segment depression on either AEM or ExT, or showing ST- segment depression with both techniques. This was also true when analy zing the cumulative survival rate until the occurrence of any endpoint . With multivariate regression analysis, ST-segment depression on AEM was the variable most strongly predictive of mortality, followed by ST -segment depression on ExT, hypertension, and diabetes. Conclusions: T hese findings illustrate the ability of AEM and ExT independently to p redict long-term cardiac mortality and morbidity rates in patients rec overing from acute myocardial infarction. The combined use of these te chniques is useful for detecting patients at high risk after acute myo cardial infarction.