title: Right-to-left frequency gradient during atrial fibrillation initiated by right atrial ectopies and its augmentation by adenosine triphosphate: Implications of right atrial fibrillation.
abstract: BACKGROUND
  A left-to-right dominant frequency (DF) gradient commonly exists in paroxysmal atrial fibrillation (AF). AF initiated by right atrial (RA) ectopy (AF-RAE) is rare.
  
  
  OBJECTIVE
  This study aimed to investigate characteristics of AF-RAE using pharmacological maneuvers and spectral analysis.
  
  
  METHODS
  Seventy-nine consecutive patients referred for catheter ablation of paroxysmal AF were enrolled. Infusions of isoproterenol and adenosine triphosphate (ATP) were used to induce AF. Patients with AF-RAE and patients with AF initiated only by pulmonary vein (PV) ectopies were classified into the RA-ectopy group (n = 7[9%]) and PV-ectopy group (n = 32[41%]), respectively. ATP was also injected during ongoing AF to unmask the driver of AF. High RA, coronary sinus, and PV-left atrial junction electrograms and electrocardiogram lead V1 underwent spectral analyses.
  
  
  RESULTS
  Patients in the RA-ectopy group were younger (51 ± 13 years vs 63 ± 7 years; P = .01) and more commonly had a family history of AF (71% vs 9%; P < .001) than patients in the PV-ectopy group. There was a baseline right-to-left DF gradient in the RA-ectopy group (PV-left atrial junction: 6.0 ± 0.4 Hz; coronary sinus: 5.7 ± 0.6 Hz; RA: 7.3 ± 0.8 Hz; P < .05) in contrast to a left-to-right DF gradient in the PV-ectopy group (5.9 ± 0.8, 5.3 ± 0.7, 5.2 ± 0.8 Hz; P < .01). ATP injection predominantly increased the DF of the high RA in the RA-ectopy group and augmented a right-to-left DF gradient (7.9 ± 1.8, 7.6 ± 1.0, 10.7 ± 0.7 Hz; P < .001), whereas it augmented a left-to-right DF gradient in the PV-ectopy group (7.9 ± 1.0, 6.4 ± 0.5, 6.6 ± 1.2 Hz; P < .05).
  
  
  CONCLUSIONS
  A rare type of paroxysmal AF initiated by RA ectopy may be maintained by a reentrant driver localized in the RA (so-called RA fibrillation).
authors.affiliation: Division of Arrhythmology, Shizuoka Saiseikai General Hospital, Shizuoka, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Hasebe
authors.affiliation: Cardiovascular Division, Ibaraki Prefectural Central Hospital, Kasama, Japan; Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan,. Electronic address: kentaroyo@nifty.com.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Division of Clinical Engineering, Shizuoka Saiseikai General Hospital, Shizuoka, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Iida
authors.affiliation: Division of Clinical Engineering, Shizuoka Saiseikai General Hospital, Shizuoka, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Hatano
authors.affiliation: Division of Clinical Engineering, Shizuoka Saiseikai General Hospital, Shizuoka, Japan.
authors.forename: Toshiro
authors.initials: T
authors.lastname: Muramatsu
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D018880:Atrial Premature Complexes / Q000175:diagnosis / Q000503:physiopathology; D002317:Cardiovascular Agents / Q000494:pharmacology; D017115:Catheter Ablation / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology*; D008875:Middle Aged; D011300:Preoperative Care
chemical_list: D002317:Cardiovascular Agents; D000255:Adenosine Triphosphate; D007545:Isoproterenol
keywords: Adenosine; Atrial fibrillation; Dominant frequency; Driver; Right atrium