Novel approaches to mechanism-based atrial fibrillation ablation

Abstract

Modern cardiac electrophysiology has reported significant advances in the understanding of mechanisms underlying complex wave propagation patterns during atrial fibrillation (AF), although disagreements remain. One school of thought adheres to the long-held postulate that AF is the result of randomly propagating wavelets that wonder throughout the atria. Another school supports the notion that AF is deterministic in that it depends on a small number of high-frequency rotors generating three-dimensional scroll waves that propagate throughout the atria. The spiralling waves are thought to interact with anatomic and functional obstacles, leading to fragmentation and new wavelet formation associated with the irregular activation patterns documented on AF tracings. The deterministic hypothesis is consistent with demonstrable hierarchical gradients of activation frequency and AF termination on ablation at specific (non-random) atrial regions. During the last decade, data from realistic animal models and pilot clinical series have triggered a new era of novel methodologies to identify and ablate AF drivers outside the pulmonary veins. New generation electroanatomical mapping systems and multielectrode mapping catheters, complimented by powerful mathematical analyses, have generated the necessary platforms and tools for moving these approaches into clinical procedures. Recent clinical data using such platforms have provided encouraging evidence supporting the feasibility of targeting and effectively ablating driver regions in addition to pulmonary vein isolation in persistent AF. Here, we review state-of-the-art technologies and provide a comprehensive historical perspective, characterization, classification, and expected outcomes of current mechanistically based methods for AF ablation. We discuss also the challenges and expected future directions that scientists and clinicians will face in their efforts to understand AF dynamics and successfully implement any novel method into regular clinical practice.

Find Me If You Can: First Clinical Experience Using the Novel CARTOFINDER Algorithm in a Routine Workflow for Atrial Fibrillation Ablation

“…Despite improvements in ablation technology, imaging modalities, and ablation techniques, the recurrence of atrial arrhythmias after AF ablation still remains frequent [1,4]. Advances in mapping technologies have allowed for more detailed approaches, including panoramic and body-surface mapping for potential individual focal AF driver or rotational activity [5][6][7][8]. The elimination of these phenomena has also been linked to higher ablation success [9,10].…”

Effect of pulmonary vein isolation on rotor/multiple wavelet dynamics in persistent atrial fibrillation, association with vagal response and implications for adjunctive ablation

“…To the best of our knowledge, this therapeutic approach has not been reported. AF-driving excitations are complex, and therefore it’s important to establish a hierarchical criterion based on activation frequency so as to discern which alleged drivers are relevant for AF maintenance [ 6 ]. EXT seems to have the advantage of quantifying the burden of the single/multiple reentrant excitations in real time.…”

“…Optical mapping experiments have demonstrated that single rotor and/or multiple wavelet excitations play a role in AF maintenance [ 4 , 5 ]; their elimination and/or modification are proposed as an effective ablation strategy for PeAF [ 6 ]. A previous non-invasive mapping study reported that PeAF was maintained predominantly by drivers clustered in a few regions.…”

Advances in basic and translational research in atrial fibrillation

“…Many of these regions are empirically targeted for ablation without underlying mechanistic insights. The lack of target specifity can result in an extensive area of ablation [204]. The widely accepted mechanism underlying AF is that it is maintained by high-frequency drivers establishing a spatial hierarchy gradient of progressively slowing activation rates as the wavefronts propagate centrifugally from the source.…”