title: A method to noninvasively identify cardiac bioelectrical sources.
abstract: BACKGROUND
  We have introduced a method to guide radiofrequency catheter ablation (RCA) procedures that estimates the location of a catheter tip used to pace the ventricles and the target site for ablation using the single equivalent moving dipole (SEMD).
  
  
  OBJECTIVE
  To investigate the accuracy of this method in resolving epicardial and endocardial electrical sources.
  
  
  METHODS
  Two electrode arrays, each of nine pacing electrodes at known distances from each other, sutured on the left- and right-ventricular (LV and RV) epicardial surfaces of swine, were used to pace the heart at multiple rates, while body surface potentials from 64 sites were recorded and used to estimate the SEMD location. A similar approach was followed for pacing from catheters in the LV and RV.
  
  
  RESULTS
  The overall (RV & LV) error in estimating the interelectrode distance of adjacent epicardial electrodes was 0.38 ± 0.45 cm. The overall endocardial (RV & LV) interelectrode distance error, was 0.44 ± 0.26 cm. Heart rate did not significantly affect the error of the estimated SEMD location (P > 0.05). The guiding process error became progressively smaller as the SEMD approached an epicardial target site and close to the target, the overall absolute error was ∼ 0.28 cm. The estimated epicardial SEMD locations preserved their topology in image space with respect to their corresponding physical location of the epicardial electrodes.
  
  
  CONCLUSIONS
  The proposed algorithm suggests one can efficiently and accurately resolve epicardial electrical sources without the need of an imaging modality. In addition, the error in resolving these sources is sufficient to guide RCA procedures.
authors.affiliation: Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Kwanghyun
authors.initials: K
authors.lastname: Sohn
authors.forename: Wener
authors.initials: W
authors.lastname: Lv
authors.forename: Kichang
authors.initials: K
authors.lastname: Lee
authors.forename: Anna
authors.initials: A
authors.lastname: Galea
authors.forename: Gordon
authors.initials: G
authors.lastname: Hirschman
authors.forename: Conor
authors.initials: C
authors.lastname: Barrett
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cohen
authors.forename: Antonis A
authors.initials: AA
authors.lastname: Armoundas
mesh_terms: D000465:Algorithms; D000818:Animals; D001674:Bioelectric Energy Sources; D017115:Catheter Ablation / Q000379:methods*; D055724:Electrophysiological Phenomena; D013552:Swine
keywords: arrhythmia; catheter ablation; localization; noninvasive; single equivalent moving dipole