CHARACTERISTICS AND PROGNOSTIC IMPORTANCE OF ST-SEGMENT ELEVATION ON HOLTER MONITORING EARLY AFTER ACUTE MYOCARDIAL-INFARCTION

The correlation between episodes of ST-segment elevation on Holter mon itoring, clinical characteristics, left ventricular function, exercise testing, and long-term prognosis was determined in 123 consecutive pa tients 55 +/- 8 years old (mean +/- SD) with a first acute myocardial infarction (AMI). During 36 hours of Holter recording 11 +/- 5 days af ter AMI, 11 patients (9%) had 91 episodes of ST-segment elevation (gro up 1), whereas 112 patients had no such episodes (group 2), Most episo des of ST-segment elevation occurred in leads with pathologic Q waves or small, indistinct R waves. Large, anterior Q-wave AMIs were more pr evalent in group 1 than in group 2, and in-hospital heart failure also occurred more frequently in group 1 patients (82% vs 23%; p <0.0005). Regional and global left ventricular function was reduced in group 1 compared with group 2: ejection fraction 33 +/- 11% vs 50 +/- 11% (p = 0.0001). All episodes of ST-segment elevation were asymptomatic and d id not correlate with different indicators of myocardial ischemia. Ind eed, exercise-induced ST-segment depression was more prevalent in grou p 2 than in group 1:57 vs 18% (p <0.035). Over a mean of 5 years (rang e 4 to 6) of follow-vp, an association between episodes of ST-segment elevation on Holter monitoring and (1) cardiac death (Kaplan-Meier ana lysis; p <0.005), and (2) cardiac death and nonfatal reinfarction (Kap lan-Meier analysis; p <0.025) was found. If, however, the symptomatic need for coronary revascularization was included as an end point, no a ssociation between episodes of ST-segment elevation and long-term outc ome could be demonstrated (Kaplan-Meier analysis; p = NS).