Electrophysiologic Characteristics of Complex Fractionated Atrial Electrograms in Patients with Atrial Fibrillation

Introduction: The underlying mechanisms of complex fractionated atrial electrogram (CFAE) during radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) have not yet been clearly elucidated. We explored the relationships between CFAE and left atrial (LA) voltage, or conduction velocity (CV).
Methods and Results: In 50 patients with AF (23 paroxysmal AF [PAF], 41 males, mean age 55.76 ± 10.16 years), the CFAE (average index of fractionation of electrograms during AF by interval-analysis algorithm, cycle length [CL]≤ 120 ms) areas, voltage, and CV were measured at eight different quadrants in each patient's LA by analyzing a NavX-guided, color-coded CFAE CL map, a voltage map, and an isochronal map (500 ms pacing) generated by contact bipolar electrograms (70–100 points in the LA). The results were: (1) CFAE areas were predominantly located in the septum, roof, and LA appendage; (2) CFAE area had lower voltage than those in non-CFAE area and was surrounded by the areas of high voltage (P < 0.0001); (3) The CFAE areas had low CVs compared with non-CFAE areas (P < 0.001); and (4) The percentage of CFAE area was lower in patients with persistent atrial fibrillation (PeAF) compared with those with PAF (P < 0.05).
Conclusions: The CFAE area, which is primarily located at the septum, has a low voltage with a lower CV, and is surrounded by high-voltage areas. Underlying electroanatomical complexity is associated with clustering of CFAEs.