Simultaneous Whole-Chamber Non-contact Mapping of Highest Dominant Frequency Sites During Persistent Atrial Fibrillation: A Prospective Ablation Study.

Peter J Stafford,Nawshin Dastagir,João L Salinet,Tiago P Almeida,Frederique J Vanheusden,Alastair J Sandilands,G André Ng,Fernando S Schlindwein,Xin Li,Paulus Kirchhof,Gavin S Chu

doi:10.3389/fphys.2022.826449

Abstract

PurposeSites of highest dominant frequency (HDF) are implicated by many proposed mechanisms underlying persistent atrial fibrillation (persAF). We hypothesized that prospectively identifying and ablating dynamic left atrial HDF sites would favorably impact the electrophysiological substrate of persAF. We aim to assess the feasibility of prospectively identifying HDF sites by global simultaneous left atrial mapping.MethodsPersAF patients with no prior ablation history underwent global simultaneous left atrial non-contact mapping. 30 s of electrograms recorded during AF were exported into a bespoke MATLAB interface to identify HDF regions, which were then targeted for ablation, prior to pulmonary vein isolation. Following ablation of each region, change in AF cycle length (AFCL) was documented (≥ 10 ms considered significant). Baseline isopotential maps of ablated regions were retrospectively analyzed looking for rotors and focal activation or extinction events.ResultsA total of 51 HDF regions were identified and ablated in 10 patients (median DF 5.8Hz, range 4.4–7.1Hz). An increase in AFCL of was seen in 20 of the 51 regions (39%), including AF termination in 4 patients. 5 out of 10 patients (including the 4 patients where AF termination occurred with HDF-guided ablation) were free from AF recurrence at 1 year. The proportion of HDF occurrences in an ablated region was not associated with change in AFCL (τ = 0.11, p = 0.24). Regions where AFCL decreased by 10 ms or more (i.e., AF disorganization) after ablation also showed lowest baseline spectral organization (p < 0.033 for any comparison). Considering all ablated regions, the average proportion of HDF events which were also HRI events was 8.0 ± 13%. Focal activations predominated (537/1253 events) in the ablated regions on isopotential maps, were modestly associated with the proportion of HDF occurrences represented by the ablated region (Kendall’s τ = 0.40, p < 0.0001), and very strongly associated with focal extinction events (τ = 0.79, p < 0.0001). Rotors were rare (4/1253 events).ConclusionTargeting dynamic HDF sites is feasible and can be efficacious, but lacks specificity in identifying relevant human persAF substrate. Spectral organization may have an adjunctive role in preventing unnecessary substrate ablation. Dynamic HDF sites are not associated with observable rotational activity on isopotential mapping, but epi-endocardial breakthroughs could be contributory.

Highlights

Atrial fibrillation (AF) is the commonest cardiac arrhythmia in clinical practice, affecting 2% of the population worldwide (Nattel, 2002)
AF termination sites were the base of LAA, the left atrium (LA) roof, and the posterior wall
The present study shows that spatiotemporally dynamic Highest DF (HDF) areas throughout the LA during human in vivo persistent AF (persAF) can be prospectively, feasibly, and efficaciously targeted using a global multisite mapping approach based on an established commercial platform, even before pulmonary vein isolation (PVI). 39% of HDF-targeted lesions resulted in an AFCL increase of 10 ms or more

Summary

Introduction

Atrial fibrillation (AF) is the commonest cardiac arrhythmia in clinical practice, affecting 2% of the population worldwide (Nattel, 2002). The electrophysiological mechanisms underlying persAF and current adjunctive ablation strategies beyond pulmonary vein isolation (PVI) lack clear evidence for effectiveness (Providencia et al, 2015; Verma et al, 2015; Mohanty et al, 2018). Sheep optical mapping studies (Mandapati et al, 2000; Mansour et al, 2001; Kalifa et al, 2006) first outlined the potential of using dominant frequency (DF) assessment to detect AF driver sites, predicated around the observation of rotors (Mandapati et al, 2000), but the utility of DF is implicit with other proposed mechanisms (Kumagai et al, 2000; Lin et al, 2005; Kalifa et al, 2006). Highest DF (HDF) sites have since been shown to be spatiotemporally unstable (Lazar et al, 2004; Yokoyama et al, 2009; Habel et al, 2010; Jarman et al, 2012; Salinet et al, 2014); as a natural corollary, simultaneous multisite mapping is necessary to reliably localize atrial high DF areas

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