title: Pace mapping in the atrium using bipolar electrograms from widely spaced electrodes.
abstract: BACKGROUND
  Pace mapping is a useful tool but is of limited utility for the atrium because of poor spatial resolution. We investigated the use of bipolar electrograms recorded from widely spaced electrodes in order to improve the resolution of pace mapping.
  
  
  METHODS
  This prospective study included patients undergoing a clinical electrophysiology study. Unipolar pacing from either the superior or inferior lateral right atrium was performed to simulate atrial tachycardia. Twelve-lead electrocardiograms were recorded during pacing as a template. In addition, three intracardiac bipolar electrograms from a set of widely spaced electrodes were also recorded. Subsequently, unipolar pacing was performed from electrodes at known distances from the initial pacing site, and the morphology of P waves in the electrocardiogram and bipolar electrograms were compared with that of the template. Morphological comparison was performed by a cardiologist and by automated computerized matching. Spatial resolution was calculated as the minimum distance at which there was no match.
  
  
  RESULTS
  Fifteen patients participated in the study. Distance at which differences in morphology were noted was smaller in the bipolar electrograms compared to that indicated by P waves in the electrocardiogram, when matched by the cardiologist (6.1±3.8 mm vs. 9.9±5.2 mm, p=0.012) or by automated analysis (4±0 mm vs. 9.9±4 mm, p<0.001).
  
  
  CONCLUSIONS
  Use of three bipolar electrograms recorded from a set of widely spaced electrodes in the right atrium improves the resolution of pace mapping compared to that using P waves from surface electrocardiograms alone.
authors.affiliation: Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry 605006, India.
authors.forename: Raja J
authors.initials: RJ
authors.lastname: Selvaraj
authors.affiliation: Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry 605006, India.
authors.forename: Sreekanth
authors.initials: S
authors.lastname: Yerram
authors.affiliation: Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry 605006, India.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry 605006, India.
authors.forename: Santhosh
authors.initials: S
authors.lastname: Satheesh
authors.affiliation: Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry 605006, India.
authors.forename: Ajith Ananthakrishna
authors.initials: AA
authors.lastname: Pillai
authors.affiliation: Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry 605006, India.
authors.forename: Mahesh Kumar
authors.initials: MK
authors.lastname: Saktheeswaran
authors.affiliation: Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry 605006, India.
authors.forename: Jayaraman
authors.initials: J
authors.lastname: Balachander
keywords: Arrhythmia; Atrial arrhythmia; Computerized analysis; Mapping; Pace mapping