Stability of Rotors and Focal Sources for Human Atrial Fibrillation: Focal Impulse and Rotor Mapping (FIRM) of AF Sources and Fibrillatory Conduction

Dr. Vijay Swarup and colleagues recently published article demonstrating the results of our research on the stability of rotors and focal sources in atrial fibrillation. This is an important clinical demonstration of a sustaining mechanism of atrial fibrilation. This is the theory behind tools to ablate rotor cores for long -term improved success of AF ablation. Dr. Swarup has been one of the leader in the research and validation of this important tool which is approved by the FDA for clinical use. The tool used for this research was the “Rhythm View System” by Topera Inc. Dr. Swarup is one of the most experienced doctors in the country in the use this tool for atrial fibrillation ablation.  

VIJAY SWARUP M.D.1,*, TINA BAYKANER M.D.2, ARMAND ROSTAMIAN M.D.3, JAMES DAUBERT M.D.4, JOHN HUMMEL M.D.5, DAVID E. KRUMMEN M.D.2, RISHI TRIKHA B.S.2, JOHN M. MILLER6, GERY TOMASSONI M.D.7 and SANJIV M. NARAYAN M.D., Ph.D.8
DOI: 10.1111/jce.12559

Keywords:

atrial fibrillation; catheter ablation; FIRM mapping; focal impulse; rotors

Abstract

Introduction

Several groups report electrical rotors or focal sources that sustain atrial fibrillation (AF) after it has been triggered. However, it is difficult to separate stable from unstable activity in prior studies that examined only seconds of AF. We applied phase-based Focal Impulse and Rotor Mapping (FIRM) to study the dynamics of rotors/sources in human AF over prolonged periods of time.

Methods

We prospectively mapped AF in 260 patients (169 persistent, 61 ± 12 years) at 6 centers in the FIRM-registry, using baskets with 64 contact electrodes per atrium. AF was phase mapped (RhythmView, Topera, Menlo Park, CA). AF propagation movies were interpreted by each operator to assess the source stability/dynamics over tens of minutes before ablation.

Results

Sources were identified in 258 of 260 of patients (99%), for 2.8 ± 1.4 sources/patient (1.8 ± 1.1 in left, 1.1 ± 0.8 in right atria). While AF sources precessed in stable regions, emanating activity including spiral waves varied from collision/fusion (fibrillatory conduction). Each source lay in stable atrial regions for 4196±6360 cycles, with no differences between paroxysmal vs persistent AF (4290 ± 5847 vs 4150 ± 6604, p = 0.78), or right vs left atrial sources (p = 0.26).

Conclusions

Rotors and focal sources for human AF mapped by FIRM over prolonged time periods precess (“wobble”) but remain within stable regions for thousands of cycles. Conversely, emanating activity such as spiral waves disorganize and collide with the fibrillatory milieu, explaining difficulties in using activation mapping or signal processing analyses at fixed electrodes to detect AF rotors. These results provide a rationale for targeted ablation at AF sources rather than fibrillatory spiral waves.
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http://onlinelibrary.wiley.com/doi/10.1111/jce.12559/suppinfo