title: A priori model independent inverse potential mapping: the impact of electrode positioning.
abstract: BACKGROUND
  In inverse potential mapping, local epicardial potentials are computed from recorded body surface potentials (BSP). When BSP are recorded with only a limited number of electrodes, in general biophysical a priori models are applied to facilitate the inverse computation. This study investigated the possibility of deriving epicardial potential information using only 62 torso electrodes in the absence of an a priori model.
  
  
  METHODS
  Computer simulations were used to determine the optimal in vivo positioning of 62 torso electrodes. Subsequently, three different electrode configurations, i.e., surrounding the thorax, concentrated precordial (30 mm inter-electrode distance) and super-concentrated precordial (20 mm inter-electrode distance) were used to record BSP from three healthy volunteers. Magnetic resonance imaging (MRI) was performed to register the electrode positions with respect to the anatomy of the patient. Epicardial potentials were inversely computed from the recorded BSP. In order to determine the reconstruction quality, the super-concentrated electrode configuration was applied in four patients with an implanted MRI-conditional pacemaker system. The distance between the position of the ventricular lead tip on MRI and the inversely reconstructed pacing site was determined.
  
  
  RESULTS
  The epicardial potential distribution reconstructed using the super-concentrated electrode configuration demonstrated the highest correlation (R = 0.98; p < 0.01) with the original epicardial source model. A mean localization error of 5.3 mm was found in the pacemaker patients.
  
  
  CONCLUSIONS
  This study demonstrated the feasibility of deriving detailed anterior epicardial potential information using only 62 torso electrodes without the use of an a priori model.
authors.affiliation: Department of Cardiology, Haga Teaching Hospital, Leyweg 275, 2545 CH, The Hague, The Netherlands. a.vandergraaf@hagaziekenhuis.nl.
authors.forename: A W Maurits
authors.initials: AW
authors.lastname: van der Graaf
authors.affiliation: Department of Cardiology, Haga Teaching Hospital, Leyweg 275, 2545 CH, The Hague, The Netherlands.
authors.forename: Pranav
authors.initials: P
authors.lastname: Bhagirath
authors.affiliation: Department of Cardiology, Haga Teaching Hospital, Leyweg 275, 2545 CH, The Hague, The Netherlands.
authors.forename: Jacques
authors.initials: J
authors.lastname: de Hooge
authors.affiliation: Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Natasja M S
authors.initials: NM
authors.lastname: de Groot
authors.affiliation: Department of Cardiology, Haga Teaching Hospital, Leyweg 275, 2545 CH, The Hague, The Netherlands. mjw.gotte@hagaziekenhuis.nl.
authors.forename: Marco J W
authors.initials: MJ
authors.lastname: Götte
mesh_terms: D000328:Adult; D000368:Aged; D018780:Body Surface Potential Mapping / Q000295:instrumentation / Q000379:methods*; D003198:Computer Simulation; D004566:Electrodes; D005240:Feasibility Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D010138:Pacemaker, Artificial
keywords: Body surface potential mapping; Computational cardiac electrophysiology; Inverse procedures; Non-invasive imaging