Relationship between complex fractionated atrial electrograms during atrial fibrillation and the critical site of atrial tachycardia that develops after catheter ablation for atrial fibrillation.

Introduction: Complex fractionated atrial electrograms (CFAEs) are a substrate modification target in patients with atrial fibrillation (AF). However, whether CFAEs can be also arrhythmogenic grounds of atrial tachycardia (AT) presenting after AF ablation remains to be determined. We investigated the relationship between CFAEs and the critical site of AT after CFAE-guided AF ablation.

Methods And Results: Seventy-two patients showing AT after pulmonary vein isolation and further CFAE-guided ablation were included. The termination sites of the 95 distinct ATs were annotated on color-coded CFAE cycle maps. Of the 95 ATs, 61 (64.2%) had a termination site at the border zone of CFAE or in a highly dense CFAE area. The cycle length (CL) of the ATs terminated in the CFAE area was significantly shorter than the CL of those terminated in the non-CFAE area. The cut-off CL for ATs terminated at the CFAE area was 270 milliseconds, with sensitivity/specificity of 70%/75%. In 67.2% of the ATs terminating at the CFAE-related area, the major termination sites were the anterior wall near the LA appendage, septum and roof, whereas the peri-mitral isthmus was the most common termination site of ATs in the non-CFAE area.

Conclusions: The areas showing CFAE and their border zones were frequently associated with termination of ATs presenting after AF ablation. The mean CL of ATs originating near CFAEs was significantly shorter than that of those terminated in non-CFAE areas. The targeted CFAE areas also provided the arrhythmogenic milieu for AT developing after AF ablation.