Arrhythmias during the acute phase of reperfusion therapy for acute myocardial infarction: effects of beta-adrenergic blockade.

In 107 patients with acute myocardial infarction, the incidence of ventricular arrhythmias during the acute phase of thrombolysis was examined by means of Holter monitoring. In patients with a patient infarct-related artery as assessed angiographically at 90 minutes, the occurrence of accelerated idioventricular rhythms was noted significantly more frequently than in patients with a permanent occluded vessel. This arrhythmia peaked in the first 180 minutes after the start of thrombolysis. In addition, single ventricular premature beats and runs of ventricular tachycardia were also more common in patients with successful reperfusion. The effects of acute intravenous administration of beta-blockers were examined in 66 patients without contraindications to this therapeutic approach. There were no differences in the occurrence of any type of rhythm disorders in patients with (n = 43) or without beta-blockade (n = 23). Thus ventricular arrhythmias particularly accelerated idioventricular rhythms, and single ventricular premature beats occur more frequently in patients with a patent infarct artery within the first 24 hours after thrombolysis. Acute intravenous beta-blockade does not appear to exert significant antiarrhythmic effects during this period.