Sequence of Double Potentials Recorded by the Decapolar Electrode Placed along the Block Line Can Identify Persistent Gap Conduction

Abstract

Background: In patients with atrial flutter (AF), a complete block line of cavotricuspid isthmus (CTI) is identified by a continuous corridor of double potentials (DP) separated by an isoelectric interval. Methods: Twenty-nine patients with typical AF underwent radio-frequency (RF) catheter ablation during coronary sinus pacing. Initially, we anatomically delivered sequential point-by-point RF application in the CTI. If complete block line was not created, then we tried to assess the sequence of DP recorded by the decapolar electrode placed along the initial ablation line. Since the terminal component (DPt) reflects the persistent conduction through the initial ablation line, we hypothesized that earliest DPt with reversal of initial polarity in adjacent DPt would indicate the point of gap conduction. Results: CTI conduction was successfully interrupted by initial linear ablation in six patients (one-line group). Among other 23 patients, DPt-guided gap conductions were identified in nine patients (another one-point group). In eight of these patients, a single application of RF energy successfully interrupted CTI conduction. One-line and another one-point groups had significantly shorter application time and fluoroscopic duration compared with those of remaining 14 patients. Conclusions: Decapolar electrode placed along the block line crossing the CTI is useful to detect gap conduction which can avoid repeat scanning and lead to target ablation.