Is there a relationship between complex fractionated atrial electrograms recorded during atrial fibrillation and sinus rhythm fractionation?

BACKGROUND: Ablation of persistent atrial fibrillation (AF) may require adjunctive methods of substrate modification. Both ablation-targeting complex fractionated atrial electrograms (CFAEs) recorded during AF and fractionated electrograms recorded during sinus rhythm (sinus rhythm fractionation [SRF]) have been described. However, the relationship of CFAEs with SRF is unclear.

METHODS: Twenty patients (age 62 ± 9 years, 13 males) with persistent AF and 9 control subjects without organic heart disease or AF (age 36 ± 6 years, 4 males) underwent detailed CFAE and SRF left atrial electroanatomic maps. The overlap in left atrial regions with CFAEs and SRF was compared in the AF population, and the distribution of SRF was compared among patients with AF and normal controls. Propagation maps were analyzed to identify the activation patterns associated with SR fractionation.

RESULTS: SRF (338 ± 150 points) and CFAE (418 ± 135 points) regions comprised 29% ± 14% and 25% ± 15% of the left atrial surface area, respectively. There was no significant correlation between SRF and CFAE maps (r = .2; P = NS). On comparing patients with AF and controls, no significant difference was found in the distribution of SRF between groups (P = .74). Regions of SRF overlapped areas of wave-front collision 75% ± 13% of the time.

CONCLUSIONS: (1) There is little overlap between regions of CFAEs during AF and regions of SRF measured in the time domain or the frequency domain, (2) the majority of SRF appears to occur in regions with wave-front collision, (3) the distribution of SRF is similar in patients with AF and normal controls, suggesting that this may not have an important role in AF maintenance and may not be a suitable ablation target.