Effects of early reperfusion in acute myocardial infarction on arrhythmias induced by programmed stimulation: A prospective, randomized study

This study compares inducibility of ventricular tachyarrhythmias by programmed electrical stimulation of the heart in patients with myocardial infarction with and without reperfusion after streptokinase therapy. Sixtytwo consecutive patients admitted with an acute myocardial infarction were randomized to either combined intravenous and intracoronary streptokinase (streptokinase group) or to standard coronary care unit treatment (control group). Thirty-six of the 62 patients (21 patients from the streptokinase and 15 from the control group) with a first myocardial infarction were studied by programmed ventricular stimulation after a mean of 26 ± 14 days. No patient had a history of antiarrhythmic drug use or documentation of a ventricular arrhythmia before the initial admission. A sustained ventricular arrhythmia was induced in 10 (48%) of the 21 patients randomized to streptokinase therapy and in all 15 (100%) control patients (p < 0.001). Sustained monomorphic ventricular tachycardia was induced in 6 (29%) and 10 (67%) patients, respectively (p < 0.05). To terminate an induced arrhythmia, direct current countershock was required in 33% of patients in the streptokinase group and 73% of patients in the control group (p < 0.02). Seventeen of the 21 patients treated with streptokinase and no control patient had evidence of early reperfusion 200 ± 70 minutes after the onset of pain. In comparison with patients without early reperfusion, patients in the reperfused group bad a lower maximal serum creatine kinase value (p < 0.01), a shorter time to peak creatine kinase value (p < 0.001) and a higher angiographic left ventricular ejection fraction (62 versus 45%, p < 0.01). Induction of sustained monomorphic ventricular tachycardia correlated with absence of early reperfusion (sensitivity 74%, specificity 88%, positive predictive value 88%) and a low angiographic left ventricular ejection fraction (