Maintenance of Atrial Fibrillation: Are Reentrant Drivers With Spatial Stability the Key?

Abstract

Presented in the following review are the insights on atrial fibrillation (AF) gained from our recent simultaneous endo-epicardial transmural and panoramic optical mapping studies of the human atria that may begin to resolve the controversy about AF maintenance mechanisms.1–3 It is still hotly debated whether the sustaining mechanism of AF involves multiwavelets self-replicating across the entire atrial myocardium4 or if fibrillatory conduction in the atria is maintained by localized AF drivers.1 Even the term “AF driver,” which is widely used in the current literature,1–3,5–15 is not well defined. In this review, AF drivers are defined as one or several patient-specific localized sources of fast, repetitive activity from which activation propagates and breaks down into fibrillatory conduction in the rest of the atria, targeted ablation of drivers would slow AF, organize AF to atrial tachycardia, or terminate AF (Figure 1). Figure 1. Defining atrial fibrillation (AF) drivers. AF drivers are defined as localized sources of fast, repetitive activity from which activation propagates and breaks down into fibrillatory conduction in the rest of the atria. One or few patient-specific AF drivers may exist simultaneously or sequentially, and targeted ablation (orange stars) of AF drivers would slow, organize to atrial tachycardia (AT), or terminate AF. Light purple ovals, black arrows, and gray arrows represent the AF driver region, path of reentry, and fibrillatory conduction, respectively. IVC indicates inferior vena cava; LA, left atria; RA, right atria; and SVC, superior vena cava. Even if one is convinced that AF drivers exist, there is no clear consensus on the specific electrophysiological mechanism of AF drivers. AF drivers have been hypothesized to represent reentry circuits, rotors, focal sources, or a complex mixture of all these mechanisms. We hypothesize that human AF is maintained by a …