Cardiac dysrhythmia associated with general anaesthesia for oral surgery. Its prevention by the prophylactic use of an oral beta-adrenergic blocker.

Ninety patients, divided randomly into three groups, received either no metoprolol, 50 mg or 100 mg metoprolol as an oral premedication. The electrocardiogram was monitored throughout the procedure. It was found that both doses of metoprolol significantly reduced the incidence of cardiac dysrhythmia.