Current Hot Potatoes in Atrial Fibrillation Ablation

Abstract

Atrial fibrillation (AF) ablation has evolved to the treatment of choice for patients with drug-resistant and symptomatic AF. Pulmonary vein isolation at the ostial or antral level usually is sufficient for treatment of true paroxysmal AF. For persistent AF ablation, drivers and perpetuators outside of the pulmonary veins are responsible for AF maintenance and have to be targeted to achieve satisfying arrhythmia-free success rate. Both complex fractionated atrial electrogram (CFAE) ablation and linear ablation are added to pulmonary vein isolation for persistent AF ablation. Nevertheless, ablation failure and necessity of repeat ablations are still frequent, especially after persistent AF ablation. Pulmonary vein reconduction is the main reason for arrhythmia recurrence after paroxysmal and to a lesser extent after persistent AF ablation. Failure of persistent AF ablation mostly is a consequence of inadequate trigger ablation, substrate modification or incompletely ablated or reconducting linear lesions. In this review we will discuss these points responsible for AF recurrence after ablation and review current possibilities on how to overcome these limitations.

Anatomical and Optical Properties of Atrial Tissue: Search for a Suitable Animal Model

“…18 The most common and effective way to treat drug-resistant AF is surgical ablation of arrhythmogenic sources. 21,28 AF ablation is performed using percutaneous ablation catheters that use different physical means to destroy or electrically isolate tissue from which sources of abnormal activity are detected. 23 The vast majority of these sources have been shown to arise from left atrial muscle near orifices of pulmonary veins.…”

“…3 Hundreds of thousands of patients undergo ablation procedures to treat this potentially life-threatening condition since it greatly increases the likelihood of stroke and ventricular fibrillation. 26,28 Yet as of today, percutaneous ablation of AF sources is done in a ‘blind’ fashion due to the absence of imaging tools to identify the boundaries of ablated tissue and depth of ablation lesions. The remaining gaps in ablation lines and secondary arrhythmic triggers can then contribute to recurrence of AF via breaks in intended conduction block.…”

A decade of complex fractionated electrograms catheter-based ablation for atrial fibrillation: Literature analysis, meta-analysis and systematic review

“…In the past decade, CFAE mechanisms and the use of CFAEs as hotspots have been explored in the field of electrophysiology. The mechanisms of CFAEs are related to anatomic and electrical tissue heterogeneity (such as microstructural obstacles [32]), zones with slow conduction or collisions, pivot points at the end of functional blocks during AF [7,33], and the autonomic nervous system [34,35], especially the GPs close to PVs [9,36,37]. Thus far, mechanism studies were mainly published in 2012 and lag significantly behind mapping studies, the numbers of which increased from 2007.…”

“…subgroup analysis of patients with persistent or permanent AF, PVI plus CFAE ablation is the advised strategy, with a success rate of 58.7%. Extensive ablation of CFAEs may eliminate or isolate some of these high dominant frequency sites, decrease tissue anisotropy by microscar formation or fibroblast proliferation, and reduce anatomic complexity by reducing zones of slow conduction or zones prone to functional conduction block or the number of re-entrant wavelets to the pivot point [33,48]. In some patients, the prognosis is better if maximal CFAEs and dominant frequency gradients are present at the boundary or center of a maximal dominant frequency region [49].…”

Acute and Mid-Term Results after Pulmonary Veins Isolation Using a Novel Circular Irrigated Multielectrode Mapping and Ablation Catheter (nMARQ)

“…However, this procedure is still time consuming and requires experienced operators and centers. In addition, repeat procedures are required in a significant number of cases and recurrent PV conduction is responsible for most ablation failures in paroxysmal AF [2]. The so-called single-shot devices such as cryoballoon and pulmonary vein ablation catheter (PVAC) aimed at the creation of circumferential lesions by only a few applications have been developed and are in clinical use in the recent years [3] [4].…”