Introduction
Dual atrioventricular (AV) nodal physiology is a common finding during an electrophysiologic study. This finding provides a substrate for the common form of atrioventricular nodal reentrant tachycardia (AVNRT)1. The typical form of AVNRT (slow-fast type) shows a short R-P or a simultaneous R-P during tachycardia with heart rates usually ranging from 150/min to 220/min2. Pseudo R’ in V1 is a common feature. However, if the heart rate during tachycardia is relatively slow, junctional tachycardia (JT) emerges as part of the differential diagnosis. Notably, while catheter ablation of AVNRT has been reported with a very high success rate and low incidence of heart block2, catheter ablation of JT has a lower success rate and higher rates of complete heart block. Therefore, during the electrophysiological study, using maneuvers such as atrial overdrive pacing (AOD) and atrial extrastimulus (AES)3,4 to differentiate AVNRT and JT is important.
In this study, we reported a series of patients with slow, symptomatic typical AVNRT below 110 bpm resembling JT, which were successfully diagnosed and ablated.