B-PO05-133 ROLE OF ELECTROGRAMS RECORDED FROM THE MINI ELECTRODES IN CATHETER ABLATION OF ATRIOVENTRICULAR NODAL REENTRANT TACHYCARDIA

Abstract

Analysis of electrograms recorded from mini electrodes (MEs) (IntellaTip MiFi, Boston Scientific) has not been reported. We evaluated the additional value of MEs during ablation of atrioventricular nodal reentrant tachycardia (AVNRT). Consecutive patients with AVNRT who underwent slow pathway ablation using a MiFi catheter were included. A combined electroanatomic approach was used to identify the target site. During ablation, operators were blind to ME electrograms, and ME electrograms immediately before initiation of the first radiofrequency (RF) application were evaluated retrospectively. A total of 62 patients (47 ± 17 years, 46.8% male) with typical (n=58) and atypical (n=4) AVNRT were included. Slow pathway ablation or modification was achieved in all patients. Thirty-two patients (51.6%) showed accelerated junctional rhythm (JR) during the first RF application. Immediately before the first RF, atrial signals at the MEs were observed in 37 patients (59.7%). There was a significant association between presence of atrial signals in MEs and the occurrence of JR (OR 5.36, P=0.002). The positive and negative predictive values of the atrial signals in MEs for the JR induction during the first RF were 67.6% (25/37) and 72.0% (18/25), respectively. Amplitudes of atrial signals of the MEs were not different between patients with and without an inducible JR (0.20 ± 0.13 mV versus 0.14 ± 0.11 mV, P=0.18). Signals recorded from the MEs could be helpful in targeting the ablation point during slow pathway ablation. Ablation should be discouraged in regions with optimal bipolar electrograms not followed by adequate ME electrograms.