BASIC COMPONENTS AND PATTERNS OF ACUTE-ISCHEMIA RECOVERY ASSESSED FROM CONTINUOUS ST MONITORING IN ACUTE MYOCARDIAL-INFARCTION TREATED BY THROMBOLYTIC THERAPY

Continuous ST monitoring of the lead showing the highest ST elevation on the admission 12-lead electrocardiogram was performed in patients w ith acute myocardial infarction of 6 hours or less enrolled in the OSI RIS and GUSTO trials. ST elevation measured at j + 50 ms was averaged from all normal beats every 20 seconds. ST trends were visually analyz ed by two observers blinded from the thrombolytic treatment, its onset , and coronary angiograms performed 21 hours (median) after thrombolys is. Three basic and consecutive components were considered for analysi s: the initial amplitude of ST elevation (Al), the maximal amplitude r ecovery (REC), and the minimal ST amplitude (AZ). Prespecified pattern s (PAT) were considered: PAT I integrated permanent Al elevation follo wed by REC, PAT 2 intermittent Al elevation, and REC. Prespecified pat tern 3 was considered in absence of REC. Twenty-four-hour trends were recorded in 347 patients and judged adequate in 306 (88%) followed by angiography in 268 (77%). This group was not clinically different from the 79 patients without ST/angiography. Prespecified pattern 1 was id entified in 81%, PAT 2 in 8%, and PAT 3 in 11% of the patients. The po sitive predictive value of PAT 1 + 2 for coronary patency was 94%, the negative predictive value 72%, sensitivity 96%, and specificity 60%. A salient feature was the occurrence of ST overshoot defined by a grea ter than or equal to 1 mm increase above Ai within the first minutes o f REC. Overshoot occurred in 35% of PAT I and predicted subsequent pat ency in all but two patients. Online display of the ST trend at the be dside contributes substantially to the immediate evaluation of thrombo lytic efficacy. Finally, left ventricular ejection fraction correlated best with AZ, which may significantly contribute to assessing the eff icacy of myocardial reperfusion.