ST resolution in a single electrocardiographic lead: A simple and accurate predictor of cardiac mortality in patients with fibrinolytic therapy for acute ST-elevation myocardial infarction

Background The extent of ST-segment resolution in the 12-lead electrocardiograph (ECG) obtained early after reperfusion therapy in patients with ST-elevation myocardial infarction (MI) has been shown to predict short- and long-term mortalities. To improve the ease of this method in clinical practice, we sought to evaluate the optimal cutoffs and the prognostic value of ST resolution (STR) measured in a single ECG lead. Methods In conjunction with the Intravenous nPA for the Treatment of Infarcting Myocardium Early (InTIME)-2 study, in which patients with an ST-elevation MI of <6 hoursʹ duration were treated with alteplase or lanoteplase, 12-lead ECGs were obtained at baseline and 90 minutes after the start of fibrinolytic therapy in 3030 patients. Results There was a close correlation between the extent of the sum STR and single-lead ST-elevation resolution (r = 0.94). The optimal cutoffs for definition of single-lead complete, partial, and no-STR groups were 70% and 50% for anterior infarcts and 70% and 20% for inferior infarcts. The cardiac 30-day mortality rates for the 2 sets of risk groups by sum or single-lead STR were as follows: no resolution, 9.5% vs 10.3%; partial resolution, 5.0% vs 3.6%; complete resolution, 2.0% vs 1.2%. The predictive power was significantly better for single-lead STR. Conclusions ST resolution obtained in a single lead is an easy and accurate prognosticator of cardiac 30-day mortality in patients with ST-elevation MI. It is therefore useful for early identification of low- and high-risk subgroups after fibrinolysis and as a surrogate end point in clinical trials.