The effects of overdrive pacing and lidocaine on atrioventricular junctional rhythm in man: the role of abnormal automaticity.

Abstract

The effects of overdrive pacing and lidocaine were studied in 22 patients with atrioventricular (AV) junctional rhythms. Based on the responses to cardiac pacing and lidocaine, patients were divided into two groups. AV junctional rhythms in group I (17 patients) were suppressed by overdrive pacing, and their rates were decreased by lidocaine. Lidocaine also prolonged the junctional recovery time in these patients. AV junctional rhythms in group II (five patients) were not suppressed by overdrive pacing. In contrast, the rate increased after overdrive pacing. Lidocaine did not alter the basic cycle lengths or the recovery times of the AV junctional rhythms in this group of patients. The data suggest that AV junctional rhythms in group I were caused by normal automaticity, while those in group II were probably due to abnormal automaticity.