Contributing factors concerning inconsistencies in persistent atrial fibrillation ablation outcomes

Abstract

Background: We investigated current clinical methods for complex fractionated atrial electrogram (CFAE) classification during persistent atrial fibrillation (persAF). In particular, factors that directly influence the low reproducibility of CFAE-guided ablation outcomes in persAF therapy, such as inconsistencies in automated CFAE classification performed by different systems, the co-existence of different types of atrial electrograms (AEGs), and insufficient AEG duration for CFAE detection. Methods: 797 bipolar AEGs were exported from NavX (St. Jude Medical) from 18 persAF patients undergoing pulmonary vein isolation and roof line ablation (PVI+RL). CFE-Mean, CFE-StdDev and peak-to-peak were exported from NavX, while the interval confidence level, average and shortest complex interval – as defined by CARTO (Biosense Webster) – were calculated offline using a validated MATLAB script. Sample entropy, dominant frequency and organization index were also calculated offline. Results: First, we show that CFAE classification varies for the same individual, depending on the commercial system being used. Revised thresholds were found for the indices calculated by each system to minimize the differences in automated CFAE detection performed independently by them. Second, our results show that some AEGs are affected by PVI+RL in persAF, while others remain unaffected by it. Different types of AEGs might correlate with distinct underlying persAF mechanisms. Multivariate analysis using the multiple descriptors measured from the AEGs effectively discriminated the different types of AEGs. Finally, we show that consecutive AEGs with 2.5 s resulted in different ablation target identification using the CARTO criterion, which would affect the ablation strategy and contribute to conflicting outcomes in AEGguided ablation in persAF. Our results suggest that CARTO should consider AEGs with longer duration to measure CFAEs. Conclusions: A thorough re-evaluation of the definition of CFAE is necessary in order to refine the identification of critical atrial regions responsible for the perpetuation of the arrhythmia in patients with persAF.

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Identifiers

ORCID for Frederique Vanheusden: orcid.org/0000-0003-2369-6189

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