Rotors as Drivers of Atrial Fibrillation and Targets for Ablation

Abstract

Atrial fibrillation (AF) is the most common arrhythmia targeted by catheter ablation. Despite significant advances in our understanding of AF, ablation outcomes remain suboptimal, and this is due in large part to an incomplete understanding of the underlying sustaining mechanisms of AF. Recent developments of patient-tailored and physiology-based computational mapping systems have identified localized electrical spiral waves, or rotors, and focal sources as mechanisms that may represent novel targets for therapy. This report provides an overview of Focal Impulse and Rotor Modulation (FIRM) mapping, which reveals that human AF is often not actually driven by disorganized activity but instead that disorganization is secondary to organized rotors or focal sources. Targeted ablation of such sources alone can eliminate AF and, when added to pulmonary vein isolation, improves long-term outcome compared with conventional ablation alone. Translating mechanistic insights from such patient-tailored mapping is likely to be crucial in achieving the next major advances in personalized medicine for AF.

Pathophysiology and Management of Arrhythmias Associated with Atrial Septal Defect and Patent Foramen Ovale

“…41 Once access has been established, conventional LA mapping and ablation techniques are used similar to those employed in the normal adult population, with no evidence of any device impact on EAM function (see Figure 3, EAM generated anatomy of the right atrium, with no significant impact of device presence). The atrial arrhythmia substrate remains incompletely understood and many of the recent developments in mechanistic mapping of AF 42 have not yet been translated to the adult congenital heart disease (ACHD) population, largely because of the relatively smaller numbers of eligible patients. There is an increased incidence of atrial fibrosis in ASD patients manifesting as regions of low voltage amplitude and spontaneous electrical scarring.…”

Role of Rotors in the Ablative Therapy of Persistent Atrial Fibrillation

“…We recently showed -using wide-area mapping during spont aneous and induced AF -that the first cycles of AF after a trigger exhibit a single organised re-entrant spiral wave or focal driver (see Figure 1) that subsequently disorganises. 13 Remarkably, these AF-initiating mechanisms may be relatively spatially fixed for each patient -even for different triggers from both atria -separated by 2.1 ± 1.7 cm from trigger sites (see Figure 1). 13 Thus, AF initiation is likely to be a two-step mechanistic process, in which 1) a trigger initiates an organised spiral wave or focal source at patient-specific anatomical sites that 2) lead rapidly to disorganisation to produce the classical AF phenotype.…”

“…13 Remarkably, these AF-initiating mechanisms may be relatively spatially fixed for each patient -even for different triggers from both atria -separated by 2.1 ± 1.7 cm from trigger sites (see Figure 1). 13 Thus, AF initiation is likely to be a two-step mechanistic process, in which 1) a trigger initiates an organised spiral wave or focal source at patient-specific anatomical sites that 2) lead rapidly to disorganisation to produce the classical AF phenotype. This begs the question of whether AF maintenance is driven by self-sustaining disorganisation, or whether disorganisation is actually sustained by localised AF drivers (rotors or focal drivers).…”

A work flow to build and validate patient specific left atrium electrophysiology models from catheter measurements

“…The activation pattern in AF is complex. Depending on the driver of AF, (mother rotor, ectopic beats or multiple wavelets ( Schricker et al., 2014 )), the activation rates locally may be more or less regular. The protocol we have chosen captures the dynamic changes in pacing rate and may not characterise the electrical dynamics at faster stable activation rates.…”