Complex fractionated atrial electrogram (CFAE) region has been implicated as the substrate of atrial fibrillation (AF). However, how its electrogram morphology is generated has not been precisely evaluated. The purpose of this study was to investigate the mechanisms responsible for the genesis of the CFAE during AF. In 16 patients with paroxysmal AF, endocardial mapping of the left atrium was performed during AF using 3D non-contact mapping system (EnSite 3000). After localization of CFAE region, we examined the activation sequence of the wave during AF. Then, we compared the conduction velocity of the wave, frequency of wave break-up and wave fusion, and frequency of pivoting activation observed during AF between CFAE and non-CFAE regions. The CFAE was located in the roof (100%), anterior (50%), posterior (56%), pulmonary vein (PV) (81%), appendage (81%) and septum (81%), respectively. The area of CFAE was 13.4±5.0 cm2. During AF, 1 to 4 meandering reentrant waves with a maximum number of 2.3±0.7 were observed. The conduction velocity of the wave at the CFAE region was significantly slower than that at the non-CFAE region (0.65±0.38 vs. 2.31±0.89 m/second, p<0.0001). In addition, there were frequent episodes of pivoting conduction, wave break-up and wave fusion in the CFAE region, which were resulted in the generation of the multiple deflections of the local electrogram in the CFAE region. Thus, the frequency of the pivoting conduction (5.0±2.1 vs. 0.3±0.8 times/second, p<0.0001), wave break-up (5.5±3.8 vs. 0±0 times/second, p<0.0001) and wave fusion (6.5±5.8 vs. 3.6±3.1 times/second, p<0.05) at the CFAE region were significantly higher than those at the non-CFAE region. At the CFAE region, the wave break-up produced a new wave and the fused waves were organized into a new wave, then propagated to the next adjacent excitable region, resulted in the perpetuation of reentrant wave propagation. The multiple deflections of the electrogram at the CFAE region was generated by the slow conduction, frequent episodes of pivoting conduction, wave break-up and wave fusion. These features imply that CFAE region provide an important substrate for the perpetuation of reentrant wave propagation and maintenance of AF.
Spatial Relations between the Standard Deviation of Complex Fractionated Atrial Electrogram Intervals and Low-Voltage Areas in Patients with Atrial Fibrillation
