title: Localized rotational activation in the left atrium during human atrial fibrillation: relationship to complex fractionated atrial electrograms and low-voltage zones.
abstract: BACKGROUND
  In humans, the existence of rotors or reentrant sources maintaining atrial fibrillation (AF) and the underlying electroanatomic substrate has not been well defined.
  
  
  OBJECTIVE
  Our aim was to determine the prevalence of localized rotational activation (RotA) in the left atrium (LA) during human AF and whether complex fractionated atrial electrograms (CFAEs) or low-voltage areas colocalize with RotA sites.
  
  
  METHODS
  We prospectively studied 32 patients (mean age 57 ± 8 years; 88% with persistent AF) undergoing AF catheter ablation. Bipolar electrograms were recorded for 2.5 seconds during AF using a roving 20-pole circular catheter in the LA. RotA was defined as sequential temporal activation of bipoles around the circular catheter. Bipolar electrogram fractionation index and bipolar voltage were used to define CFAEs and low-voltage areas, respectively.
  
  
  RESULTS
  In 21 (66%) patients, 47 RotA sites were identified. Few (9%) lasted 2.5 seconds (cycle length 183 ± 6 ms), while the majority (91%) were nonsustained (duration 610 ± 288 ms; cycle length 149 ± 11 ms). RotA was most common in the pulmonary vein antrum (71%) and posterior LA (25%). CFAEs were recorded from 18% ± 12% of LA area, and most (92% ± 7%) were not associated with RotA sites. However, 85% of RotA sites contained CFAEs. Very low voltage (<0.1 mV) areas comprised 12% ± 10% of LA area and were present in 23% of RotA sites.
  
  
  CONCLUSIONS
  In patients with predominantly persistent AF, localized RotA is commonly present but tends to be transient (<1 second). Although most CFAEs do not colocalize with RotA sites, the high prevalence of CFAEs and very low voltages within RotA sites may indicate slow conduction in diseased myocardium necessary for their maintenance.
authors.affiliation: Department of Engineering, Rochester Institute of Technology, Rochester, New York.
authors.forename: B
authors.initials: B
authors.lastname: Ghoraani
authors.forename: R
authors.initials: R
authors.lastname: Dalvi
authors.forename: S
authors.initials: S
authors.lastname: Gizurarson
authors.forename: M
authors.initials: M
authors.lastname: Das
authors.forename: A
authors.initials: A
authors.lastname: Ha
authors.forename: A
authors.initials: A
authors.lastname: Suszko
authors.forename: S
authors.initials: S
authors.lastname: Krishnan
authors.forename: V S
authors.initials: VS
authors.lastname: Chauhan
mesh_terms: D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery; D017115:Catheter Ablation; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
keywords: AF; Activation; Atrial fibrillation; Bipolar voltage; CFAE; CL; Catheter ablation; EGM; FI; Fractionation; IQR; LA; PV; RotA; Rotation; VLV; atrial fibrillation; complex fractionated atrial electrogram; cycle length; electrogram; fractionation index; interquartile range; left atrium/atrial; pulmonary vein; rotational activation; very low voltage