EXTENT OF EARLY ST SEGMENT ELEVATION RESOLUTION - A SIMPLE BUT STRONGPREDICTOR OF OUTCOME IN PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION

Objectives. This study proposed to verify the prognostic power of earl y ST segment elevation resolution in patients with acute myocardial in farction from the Intravenous Streptokinase in Acute Myocardial Infarc tion study data base. Background. Data from a small prospective study suggested that use of two cutoff points for three different levels of ST segment resolution 3 h after the start of thrombolysis may be an ef ficient way to predict outcome in an individual patient. Methods. The three groups of ST segment resolution were defined as 1) complete reso lution (greater than or equal to 70% [552 patients]) or only slight ST segment elevation (127 patients); 2) partial resolution (<70% to 30% [475 patients]); 3) no resolution (<30% to >0% [362 patients]). Infarc t size was measured from creatine kinase isoenzyme, MB fraction, relea se and from the number of Q waves. Left ventricular function was asses sed in 818 patients 1 month after infarction. Results. For complete, p artial and no ST segment resolution 3 h after the start of streptokina se or placebo infusion, enzyme release was 1.2, 1.8 and 2.1 IU/ml x h; number of Q waves 1.7, 2.5 and 3.0; and ejection fraction 60%, 53% an d 49%, respectively (all adjusted p = 0.0000). Mortality rate at 21 da ys was 2.2%, 3.4% and 8.6%, respectively. No ST segment resolution was the most powerful independent predictor of early mortality (p = 0.000 1). Survival rate curves at 6-year follow-up showed significant mortal ity differences with increasing divergence (p = 0.0003 anterior infarc tion; p = 0.005 inferior infarction). In subgroups with an overall hig her risk of dying, mortality was strongly determined by the extent of early ST segment resolution. Conclusions. The extent of ST segment ele vation resolution conveys useful early information about outcome in an individual patient after acute myocardial infarction.