The continuous challenge of AF ablation: From foci to rotational activity

Abstract

Pulmonary vein isolation (PVI) is central to ablation approaches for atrial fibrillation (AF), yet many patients still have arrhythmia recurrence after one or more procedures despite the latest technology for PVI. Ablation of rotational or focal sources for AF, which lie outside the pulmonary veins in many patients, is a practical approach that has been shown to improve success by many groups. Localized sources lie in atrial regions shown mechanistically to sustain AF in optical mapping and clinical studies of human AF, as well as computational and animal studies. Because they arise in localized atrial regions, AF sources may explain central paradoxes in clinical practice – such as how limited ablation in patient specific sites can terminate persistent AF yet extensive anatomical ablation at stereotypical locations, which should extinguish disordered waves, does not improve success in clinical trials. Ongoing studies may help to resolve many controversies in the field of rotational sources for AF. Studies now verify rotational activation by multiple mapping approaches in the same patients, at sites where ablation terminates persistent AF. However, these studies also show that certain mapping methods are less effective for detecting AF sources than others. It is also recognized that the success of AF source ablation is technique dependent. This review article provides a mechanistic and clinical rationale to ablate localized sources (rotational and focal), and describes successful techniques for their ablation as well as pitfalls to avoid. We hope that this review will serve as a platform for future improvements in the patient-tailored ablation for complex arrhythmias.

Atrial Rotor Dynamics Under Complex Fractional Order Diffusion

“…The focal ectopic activity is an important source of reentrant propagation (Haïssaguerre et al, 1998 ; Arora et al, 2003 ). There is experimental evidence suggesting that the mechanisms determining the tissue vulnerability to reentry are related with structural and electrical remodeling interactions (Narayan et al, 2017 ). The complex fractional model reveals that increasing the degrees of structural heterogeneity increase the VW.…”

Rotational Drivers in Atrial Fibrillation

“…One future approach to reconcile AF mapping is compare methods with complementary strengths, for instance phase mapping (sensitive for rotations) with traditional mapping (specific 14 ). Recent efforts are making AF mapping software and data freely available online 16 .…”

Looking for new frontiers in atrial fibrillation ablation. A remaining challenge for health care

“…12,13 Also, different technical approaches may contribute to improve the efficacy and safety of ablation, particularly concerning persistent AF. Therefore, this issue of the Portuguese Journal of Cardiology also includes extensive data about the advantages and drawbacks of cryoballoon ablation, 14 substrate modification, based on isolation of atrial fibrotic areas, 15 and complete isolation of the left atrial appendage.…”