Presence of Left-to-Right Atrial Frequency Gradient in Paroxysmal but Not Persistent Atrial Fibrillation in Humans

Lazar, Sorin; Dixit, Sanjay; Marchlinski, Francis E.; Callans, David J.; Gerstenfeld, Edward P.

doi:10.1161/01.cir.0000147279.91094.5e

Cited by 285 publications

(265 citation statements)

References 24 publications

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“…This gradient, however, was not present among patients with persistent AF, again suggesting a different mechanism for sustaining AF of longer duration. 30 The correlation between sites of high DF and rotor-like activity was not assessed in this study. In a later study by the same group, atrial DF gradients were assessed before and after pulmonary vein isolation (PVI).…”

Section: Evidence For Rotors and Other High Frequency Sources As Drivmentioning

confidence: 92%

Mechanisms of Atrial Fibrillation – Reentry, Rotors and Reality

Waks

Josephson²

2014

Arrhythmia &Amp; Electrophysiology Review

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Atrial fibrillation (AF), the most common sustained arrhythmia, is a leading cause of stroke, and is associated with significant morbidity and mortality worldwide. Despite its frequency, clinical importance, and advances in technology and our knowledge of the molecular, ionic and physiological fundamentals of cardiac electrophysiology, our limited understanding of the mechanisms that initiate and sustain AF has prevented us from being able to truly cure this arrhythmia with antiarrhythmic drugs and/or ablation. This contrasts with other arrhythmias, such as AV nodal tachycardia or circus movement tachycardia using an accessory pathway, which have well-defined mechanisms and circuits that can be safely targeted with high rates of cure. The observations that AF may have different mechanisms in different patients, and that paroxysmal, persistent and permanent forms of AF may differ in how they are initiated and sustained, only serves to reinforce our lack of understanding of this ubiquitous arrhythmia. Historical Mechanisms of Atrial Fibrillation and the Multiple Wavelet HypothesisInterest and understanding of the mechanism of AF began to take form in the early 1900s. Given the chaotic and irregular nature of AF on the surface electrocardiogram, rapid firing of automatic atrial foci was considered a potential mechanism. However, after the seminal work of Mayer 1 , Mines 2 and Garrey 3 in laying the foundation for describing and understanding reentrant arrhythmias, atrial reentrant circuits emerged as the likely drivers of AF.4-7 Although these theories were conceptually sound, it was impossible to prove a specific mechanism with the technology of the time. Moe et al. demonstrated that it was probabilistically unlikely that a large number of simultaneous wavefronts would all die out simultaneously, and AF would therefore perpetuate. However, if the number of simultaneous wavelets were small and/or below a critical value (between 15 and 30 in Moe's computer model), 9 at some point all reentrant wavefronts would be simultaneously extinguished, and AF would therefore terminate. 8,9 Allessie et al. provided experimental evidence supporting this mechanism in a canine heart model of AF where four to six simultaneous reentrant wavelets were needed to sustain arrhythmia. 10 Further evidence supporting multiple wavelets in AF was demonstrated in a separate model, which evaluated the effect of various antiarrhythmic drugs on canine myocardium. This model demonstrated that termination of AF was associated with a reduction AbstractAtrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice, yet our understanding of the mechanisms that initiate and sustain this arrhythmia remains quite poor. Over the last 50 years, various mechanisms of AF have been proposed, yet none has been consistently observed in both experimental studies and in humans. Recently, there has been increasing interest in understanding how spiral waves or rotors -which are specific, organised forms of functional reentry -su...

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Section: Evidence For Rotors and Other High Frequency Sources As Drivmentioning

confidence: 92%

Mechanisms of Atrial Fibrillation – Reentry, Rotors and Reality

Waks

Josephson²

2014

Arrhythmia &Amp; Electrophysiology Review

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“…1 The precise mechanisms that initiate and maintain human AF are not well understood. Part of the reason for this incomplete understanding is the difficulty in obtaining accurate human maps of spatio-temporally varying electrical activity in AF, and hence explaining consistent spatial gradients in rate and dominant frequency 2 and electrical propagation. 3 High resolution mapping techniques, especially ones using optical dyes, have proven to be instrumental in determining the spatio-temporal wave organization in animal models and in explanted human hearts.…”

Section: Introductionmentioning

confidence: 99%

Theoretical considerations for mapping activation in human cardiac fibrillation

Rappel

Narayan²

2013

Chaos: An Interdisciplinary Journal of Nonlinear Science

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Defining mechanisms for cardiac fibrillation is challenging because, in contrast to other arrhythmias, fibrillation exhibits complex non-repeatability in spatiotemporal activation but paradoxically exhibits conserved spatial gradients in rate, dominant frequency, and electrical propagation. Unlike animal models, in which fibrillation can be mapped at high spatial and temporal resolution using optical dyes or arrays of contact electrodes, mapping of cardiac fibrillation in patients is constrained practically to lower resolutions or smaller fields-of-view. In many animal models, atrial fibrillation is maintained by localized electrical rotors and focal sources. However, until recently, few studies had revealed localized sources in human fibrillation, so that the impact of mapping constraints on the ability to identify rotors or focal sources in humans was not described. Here, we determine the minimum spatial and temporal resolutions theoretically required to detect rigidly rotating spiral waves and focal sources, then extend these requirements for spiral waves in computer simulations. Finally, we apply our results to clinical data acquired during human atrial fibrillation using a novel technique termed focal impulse and rotor mapping (FIRM). Our results provide theoretical justification and clinical demonstration that FIRM meets the spatio-temporal resolution requirements to reliably identify rotors and focal sources for human atrial fibrillation. Atrial fibrillation (AF) is the most common heart rhythm disorder (cardiac arrhythmia) in the United States that may cause substantial morbidity and mortality. However, the precise mechanisms causing AF are still not well understood, partly due to difficulties in reliably mapping electrical activity during the spatio-temporal variations of AF in patients. In this article, we determine the minimal spatial and temporal resolution required to accurately map in humans the electrical rotors and focal sources shown to sustain AF in various model systems. We first test these requirements in computer simulations. We then validate that a recently developed mapping technique which employs bi-atrial multielectrode contact arrays is able to capture localized rotors and focal sources for human AF.

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“…The result of regression or classification can be then used as a number (color shade) to be mapped into real electro-anatomical maps during the ablation of AF. In the era of catheter ablation of AF, the initial attempts to describe A-EGMs during AF were predominantly based on frequency-domain analysis of atrial signals (Sanders et al, 2005), (Lazar et al, 2004) and (Lin et al, 2006). Wave morphology similarity approach was alternatively investigated (Ravelli et al, 2005).…”

Section: Discussionmentioning

confidence: 99%