The electrophysiologic effects of intravenous lidocaine in the Wolff-Parkinson-White syndrome.

Twelve patients with the Wolff-Parkinson-White syndrome underwent electrophysiologic study, before and after the bolus intravenous administration of lidocaine, 1 mg./kg. There was no significant increase in the effective refractory period of the anterograde AV node pathway, the anterograde or retrograde accessory pathway, or the atrial or ventricular muscle; intravenous bolus administration of lidocaine is unlikely to terminate the re-entry tachycardias, or decrease the rate of the ventricular response in atrial fibrillation, in the WPW syndrome. There was no significant increase in the anterograde or retrograde AV conduction times; bolus administration of lidocaine is unlikely to decrease the rates of the re-entry tachycardias. In addition, lidocaine failed to alter significantly features related to tachycardia initiation. Except in isolated, unpredictable cases, intravenous bolus administration of lidocaine is not likely to be of benefit in the supraventricular tachyarrhythmias of the WPW syndrome.