Anatomical targets and expected outcomes of catheter‐based ablation of atrial fibrillation in 2020

Abstract

Anatomical‐based approaches, targeting either pulmonary vein isolation (PVI) or additional extra PV regions, represent the most commonly used ablation treatments in symptomatic patients with atrial fibrillation (AF) recurrences despite antiarrhythmic drug therapy. PVI remains the main anatomical target during catheter‐based AF ablation, with the aid of new technological advances as contact force monitoring to increase safety and effective radiofrequency (RF) lesions. Nowadays, cryoballoon ablation has also achieved the same level of scientific evidence in patients with paroxysmal AF undergoing PVI. In parallel, electrical isolation of extra PV targets has progressively increased, which is associated with a steady increase in complex cases undergoing ablation. Several atrial regions as the left atrial posterior wall, the vein of Marshall, the left atrial appendage, or the coronary sinus have been described in different series as locations potentially involved in AF initiation and maintenance. Targeting these regions may be challenging using conventional point‐by‐point RF delivery, which has opened new opportunities for coadjuvant alternatives as balloon ablation or selective ethanol injection. Although more extensive ablation may increase intraprocedural AF termination and freedom from arrhythmias during the follow‐up, some of the targets to achieve such outcomes are not exempt of potential severe complications. Here, we review and discuss current anatomical approaches and the main ablation technologies to target atrial regions associated with AF initiation and maintenance.

Novel approaches to mechanism-based atrial fibrillation ablation

“… 40 Since then, the role of PVs on AF initiation has mobilized a tremendous amount of predominantly private funding to achieve rapid, effective, and safe PVI using different technologies like single-shot devices, 41 contact force monitoring, or high-resolution electroanatomical mapping, 42 , 43 among others. 5 Conversely, experimental data for the necessary understanding of the mechanisms underlying AF maintenance beyond the PVs have been much more limited and mainly associated with public funding agencies. 44 , 45 …”

“…A common strategy to treat symptomatic AF episodes after permanent PVI is to ablate other atrial anatomical targets, potentially associated with AF initiation and maintenance. 5 Among other regions, the posterior left atrial wall, the vein of Marshall, and the left atrial appendage (LAA) have been reported to be locations for AF triggers outside de PVs in some series. 5–7 Moreover, extra-PV trigger locations may also participate in AF maintenance as areas for driver sources sustaining the overall arrhythmia.…”

“… 5 Among other regions, the posterior left atrial wall, the vein of Marshall, and the left atrial appendage (LAA) have been reported to be locations for AF triggers outside de PVs in some series. 5–7 Moreover, extra-PV trigger locations may also participate in AF maintenance as areas for driver sources sustaining the overall arrhythmia. 8 , 9 However, many of these atrial regions are empirically targeted for ablation without robust underlying supportive mechanistic insights.…”

“… 10 Some regions may require ablating extensive areas because of lack of target specificity. 5 This is highly relevant since the larger the ablated area outside the PVs the higher the risk of severe complications. 11 …”

Mapping Technologies for Catheter Ablation of Atrial Fibrillation Beyond Pulmonary Vein Isolation

“…However, the optimal ablation strategy beyond pulmonary vein isolation (PVI) for PersAF remains unclear. [ 3 ] A wide variety of adjunctive ablation strategies have been explored, such as linear ablation, posterior wall isolation, ganglionic plexus ablation, isolation of the left atrial appendage, or substrate modification of areas with low voltage and fibrosis among others. [ 4 – 9 ] While incremental benefit has been reported with some of these approaches, other studies have failed to show any advantage.…”