EARLY RECURRENT ST SEGMENT ELEVATION DURING CONTINUOUS ECG MONITORING OF MYOCARDIAL-INFARCTION PATIENTS UNDERGOING THROMBOLYSIS

Early fluctuations of the ST-segment elevation indicating intermittent opening and reocclusion of the infarct artery has been well documented by angiographic monitoring in individual acute myocardial infarction patients undergoing thrombolytic therapy. However, the frequency of such episodes has not been studied in a consecutive patient group. Furthermore, it is not known what impact this finding has on the reinfarction risk during hospitalization and on left ventricular healing. The present investigation included 79 patients with acute myocardial infarction (pain less-than-or-equal-to 6 h). Continuous Holter monitoring of the infarct-related ST elevation was initiated before or directly after starting thrombolytic therapy. During the 24-h observation period, 34 patients (43%) showed episodes of recurrent ST elevation after an initial resolution (group 1). Among those without episodes, ST elevation resolved within 4 h in 34 (43 %, group 2) and persisted greater-than-or-equal-to 4 h in 11 (1 4 %, group 3). Episodes of re-elevation were more frequent during the first 4 h (0.25 episodes per hour) than in the late part of the observation period (0.04 episodes per hour). Most episodes were transient and short lasting; only nine patients showed persistent re-elevations longer than 60 min. During hospitalization, group 1 patients had a higher incidence of reinfarctions and severe ischemic events than those without episodes (group 1 12/34 (35 %) vs. group 2 4/34 (12%) vs. group 31/11 (9%), p = 0.03). At angiography after 9 days, the proportion of occluded infarct-related arteries was significantly higher at 52 % in patients with episodes, than in those of group 2 (24 %, p = 0.02) and was comparable to that found in those without early resolution of the ST elevation (group 3, 38 %). The three patient groups did not differ significantly in the angiographic assessment of global and regional left ventricular function 9 days after the infarct. Early episodes of fluctuating ST segment elevation during continuous monitoring in patients receiving thrombolytic therapy are indicative of an unstable stenosis. Their detection points to a higher risk of reinfarction and permanent occlusion of the infarct artery. However, the frequency of early recurrent ST-segment elevation may necessitate further characterization of high-risk ECG patterns before this technique can be applied to identify patients who may profit from early invasive procedures.