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. Sixty-two 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 less than 0.001). Sustained monomorphic ventricular tachycardia was induced in 6 (29%) and 10 (67%) patients, respectively (p less than 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 less than 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 had a lower maximal serum creatine kinase value (p less than 0.01), a shorter time to peak creatine kinase value (p less than 0.001) and a higher angiographic left ventricular ejection fraction (62 versus 45%, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)