Validating left atrial fractionation and low-voltage substrate during atrial fibrillation and sinus rhythm-A high-density mapping study in persistent atrial fibrillation

Taiyuan Huang; Juan Chen; Björn Müller-Edenborn; Louisa Mayer; Martin Eichenlaub; Zoraida Moreno Weidmann; Juergen Allgeier; Marius Bohnen; Heiko Lehrmann; Dietmar Trenk; Simon Schoechlin; Dirk Westermann; Thomas Arentz; Amir Jadidi

doi:10.3389/fcvm.2022.1000027

Validating left atrial fractionation and low-voltage substrate during atrial fibrillation and sinus rhythm-A high-density mapping study in persistent atrial fibrillation

Front Cardiovasc Med. 2022 Oct 18:9:1000027. doi: 10.3389/fcvm.2022.1000027. eCollection 2022.

Authors

Affiliations

¹ Department of Cardiology, Arrhythmia Division, Faculty of Medicine, University Heart Center Freiburg-Bad Krozingen, University of Freiburg, Freiburg im Breisgau, Germany.
² Department of Cardiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China.
³ Arrhythmia Unit, Department of Cardiology, Hospital Universitario Sant Pau, Barcelona, Spain.

Abstract

Background: Low-voltage-substrate (LVS)-guided ablation for persistent atrial fibrillation (AF) has been described either in sinus rhythm (SR) or AF. Prolonged fractionated potentials (PFPs) may represent arrhythmogenic slow conduction substrate and potentially co-localize with LVS. We assess the spatial correlation of PFP identified in AF (PFP-AF) to those mapped in SR (PFP-SR). We further report the relationship between LVS and PFPs when mapped in AF or SR.

Materials and methods: Thirty-eight patients with ablation naïve persistent AF underwent left atrial (LA) high-density mapping in AF and SR prior to catheter ablation. Areas presenting PFP-AF and PFP-SR were annotated during mapping on the LA geometry. Low-voltage areas (LVA) were quantified using a bipolar threshold of 0.5 mV during both AF and SR mapping. Concordance of fractionated potentials (CFP) (defined as the presence of PFPs in both rhythms within a radius of 6 mm) was quantified. Spatial distribution and correlation of PFP and CFP with LVA were assessed. The predictors for CFP were determined.

Results: PFPs displayed low voltages both during AF (median 0.30 mV (Q1-Q3: 0.20-0.50 mV) and SR (median 0.35 mV (Q1-Q3: 0.20-0.56 mV). The duration of PFP-SR was measured at 61 ms (Q1-Q3: 51-76 ms). During SR, most PFP-SRs (89.4 and 97.2%) were located within LVA (<0.5 mV and <1.0 mV, respectively). Areas presenting PFP occurred more frequently in AF than in SR (median: 9.5 vs. 8.0, p = 0.005). Both PFP-AF and PFP-SR were predominantly located at anterior LA (>40%), followed by posterior LA (>20%) and septal LA (>15%). The extent of LVA < 0.5 mV was more extensive in AF (median: 25.2% of LA surface, Q1-Q3:16.6-50.5%) than in SR (median: 12.3%, Q1-Q3: 4.7-29.4%, p = 0.001). CFP in both rhythms occurred in 80% of PFP-SR and 59% of PFP-AF (p = 0.008). Notably, CFP was positively correlated to the extent of LVA in SR (p = 0.004), but not with LVA in AF (p = 0.226). Additionally, the extent of LVA < 0.5 mV in SR was the only significant predictor for CFP, with an optimal threshold of 16% predicting high (>80%) fractionation concordance in AF and SR.

Conclusion: Substrate mapping in SR vs. AF reveals smaller areas of low voltage and fewer sites with PFP. PFP-SR are located within low-voltage areas in SR. There is a high degree of spatial agreement (80%) between PFP-AF and PFP-SR in patients with moderate LVA in SR (>16% of LA surface). These findings should be considered when substrate-based ablation strategies are applied in patients with the left atrial low-voltage substrate with recurrent persistent AF.

Keywords: atrial late potentials; catheter ablation; low voltage; mapping; persistent atrial fibrillation; prolonged fractionated potential; pulmonary vein isolation; substrate.