title: Epicardial and endocardial dispersion of ventricular repolarization. A study of monophasic action potential mapping in healthy pigs.
abstract: OBJECTIVE
  To investigate the total dispersion of ventricular repolarization of the epi- and endocardium.
  
  
  METHODS
  Monophasic action potentials (MAP) were recorded from 211+/-54 (151-353) left and right ventricular epi- and endocardial sites during atrial pacing in 10 pigs using the CARTO system. The activation time (AT), MAP duration (MAPd) and end of repolarization time (EOR) were measured.
  
  
  RESULTS
  The total dispersion of AT, EOR and MAPd, defined as the maximal differences of these parameters over both the epi- and endocardium, were 57+/-10, 84+/-20, and 75+/-21 ms respectively and were significantly larger than the respective epi- and endocardial dispersions (p<0.05). The epicardial dispersion of AT, EOR and MAPd of both the right and left ventricles were significantly larger than that of each ventricle alone (p<0.02). Sternotomy did not affect these dispersion parameters.
  
  
  CONCLUSIONS
  Detailed mapping of epicardial repolarization in vivo using the MAP mapping technique is feasible. Both the epi- and endocardium of the two ventricles contribute significantly to the total dispersion of repolarization.
authors.affiliation: Department of Cardiology, University Hospital, Lund, Sweden. Ole.kongstad@skane.se
authors.forename: Ole
authors.initials: O
authors.lastname: Kongstad
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Xia
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Liang
authors.forename: Eva
authors.initials: E
authors.lastname: Hertervig
authors.forename: Erik
authors.initials: E
authors.lastname: Ljungström
authors.forename: Bertil
authors.initials: B
authors.lastname: Olsson
authors.forename: Shiwen
authors.initials: S
authors.lastname: Yuan
mesh_terms: D000200:Action Potentials; D000818:Animals; D018780:Body Surface Potential Mapping; D002304:Cardiac Pacing, Artificial; D004699:Endocardium / Q000502:physiology*; D006329:Heart Conduction System / Q000502:physiology*; D010496:Pericardium / Q000502:physiology*; D013552:Swine; D013997:Time Factors; D016276:Ventricular Function