Stability of rotors and focal sources for human atrial fibrillation: Focal impulse and rotor mapping (firm) of AF sources and fibrillatory conduction

Vijay Swarup, Tina Baykaner, Armand Rostamian, James P. Daubert, John Hummel, David E. Krummen, Rishi Trikha, John M. Miller, Gery F. Tomassoni, Sanjiv M. Narayan

Research output: Contribution to journalArticle

34 Scopus citations


Stable Human AF Rotors 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, USA). 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 4,196 ± 6,360 cycles, with no differences between paroxysmal versus persistent AF (4,290 ± 5,847 vs. 4,150 ± 6,604; P = 0.78), or right versus 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.

Original languageEnglish (US)
Pages (from-to)1284-1292
Number of pages9
JournalJournal of Cardiovascular Electrophysiology
Issue number12
StatePublished - Dec 1 2014



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

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Swarup, V., Baykaner, T., Rostamian, A., Daubert, J. P., Hummel, J., Krummen, D. E., Trikha, R., Miller, J. M., Tomassoni, G. F., & Narayan, S. M. (2014). Stability of rotors and focal sources for human atrial fibrillation: Focal impulse and rotor mapping (firm) of AF sources and fibrillatory conduction. Journal of Cardiovascular Electrophysiology, 25(12), 1284-1292.