Characterization of bipolar electrograms during sinus rhythm for complex fractionated atrial electrograms recorded in patients with paroxysmal and persistent atrial fibrillation

Abstract

Complex fractionated atrial electrogram (CFAE) has been reported to relate to maintain atrial fibrillation (AF). The aims of this study were to investigate the relationship between CFAE and background conditions during sinus rhythm (SR). Electroanatomical mapping using an EnSite Array was performed in 20 patients (paroxysmal AF:persistent AF = 16:4) who underwent pulmonary vein antrum isolation (PVAI). Contact bipolar electrograms were recorded before PVAI, during SR, and subsequently during induced AF. Peak-to-peak voltages and morphologies of the electrograms during SR were compared between sites with and without CFAE during AF. Among 1947 points obtained during SR, 974 (50%) were included in CFAE sites and 973 (50%) in non-CFAE sites. Electrogram amplitude during SR was higher at the CFAE sites than at the non-CFAE sites (2.4 +/- 1.7 vs. 1.9 +/- 1.9 mV; P < 0.0001), whereas fractionated or double electrograms were found in a similar range between the two areas (2 vs. 3%; P = 0.21). When analysed further in terms of AF termination by PVAI followed by confirmation of non-inducibility, the voltage of electrograms at the CFAE sites was lower (2.1 +/- 1.7 vs. 2.6 +/- 1.8 mV; P = 0.0001) and the morphology was more complex in patients without AF termination compared with those with AF termination. Our results suggest that in paroxysmal and persistent AF with minimally damaged LA, the CFAE sites in patients with AF termination by PVAI alone represent healthy atrial tissue with rapid electrical activity in response to an AF driver located in the pulmonary vein. However, in patients without AF termination, they represent more damaged tissue responsible for maintaining AF.