title: Ability of magnetocardiography to detect regional dominant frequencies of atrial fibrillation.
abstract: BACKGROUND
  Lead V1 on electrocardiography (ECG) can detect the dominant frequency (DF) of atrial fibrillation (AF) in the right atrium (RA). Paroxysmal AF is characterized by a frequency gradient from the left atrium (LA) to the right atrium (RA). We examined the ability of magnetocardiography (MCG) to detect regional DFs in both the atria.
  
  
  METHODS
  Study subjects comprised 18 consecutive patients referred for catheter ablation of persistent AF. An MCG system with 64 magnetic sensors was used to perform MCG in the frontal, lateral, and back planes prior to the ablation procedure in each patient. DFMCG and organization index (OIMCG) were calculated using fast Fourier transformation. Intracardiac electrograms (ICEs) in both the atria and the coronary sinus (CS) were mapped at 17 sites. Regional DFsICE were also determined.
  
  
  RESULTS
  Mean LA DFICE was higher than mean RA DFICE (6.40±0.66 versus 6.16±0.80 Hz, P=0.03). DFMCG in the channel having the highest OIMCG was 6.61±0.88 Hz in the frontal plane, 6.52±0.64 Hz in the lateral plane, and 6.42±0.62 Hz in the back plane (P=0.3). In each plane, DFMCG correlated with DFICE at the RA appendage (R=0.95, P<0.0001), the LA appendage (R=0.91, P<0.0001), and the CS (R=0.93, P<0.0001). DFECG in V5 modestly correlated with DFICE at the LA appendage (R=0.82, P<0.0001).
  
  
  CONCLUSIONS
  MCG could more precisely detect the DFs in the LA and the CS than ECG. However, the usefulness of pre-procedural detection of the AF frequency gradient for ablation therapy needs to be evaluated in future prospective studies.
authors.affiliation: Division of Cardiovascular Medicine, University of Tsukuba, Tsukuba, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Advanced Research Laboratory, Hitachi Ltd., Kokubunji, Japan.
authors.forename: Kuniomi
authors.initials: K
authors.lastname: Ogata
authors.affiliation: Division of Cardiovascular Medicine, University of Tsukuba, Tsukuba, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Inaba
authors.affiliation: Division of Cardiovascular Medicine, University of Tsukuba, Tsukuba, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nakazawa
authors.affiliation: Division of Cardiovascular Medicine, University of Tsukuba, Tsukuba, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Ibaraki Health Service Association, Mito, Japan.
authors.forename: Iwao
authors.initials: I
authors.lastname: Yamaguchi
authors.affiliation: Advanced Research Laboratory, Hitachi Ltd., Kokubunji, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kandori
authors.affiliation: Division of Cardiovascular Medicine, University of Tsukuba, Tsukuba, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
keywords: Atrial fibrillation; Dominant frequency; Magnetocardiography