Paradoxic acceleration of ventricular rate after therapy with lidocaine and ajmaline. Findings in two patients with supraventricular tachyarrhythmia.

In two patients with supraventricular tachyarrhythmias with atrioventricular block, therapy with lidocaine and ajmaline decreased the atrioventricular block and caused paradoxic acceleration of the ventricular rate. Appropriate treatment of this hazardous result of therapy with antiarrhythmic drug is reviewed.