title: Ventricular repolarization sequences on the epicardium and endocardium. Monophasic action potential mapping in healthy pigs.
abstract: To investigate repolarization sequence, monophasic action potentials were recorded from a mean of 153 ± 54 left and right ventricular epicardial and endocardial sites in 10 pigs using the CARTO mapping system (Biosense Webster, Waterloo, Belgium). The activation time and end-of-repolarization (EOR) time were measured and 3-dimensional maps of activation and repolarization sequences constructed.
  
  
  RESULTS
  In 8 of 9 pigs, both the activation and EOR times appeared first in the septum and last in the latero-basal areas on the endocardium, not on the epicardium. The EOR followed the activation sequence, both on the epicardium (in 8/9 pigs) and endocardium (in 8/8 pigs). The maximal EOR differences were 84 ± 20 ms, whereas the local EOR differences between paired sites against each other on the left ventricular epicardium and endocardium were 11 ± 9 ms in the apex and 12 ± 12 ms in the anterior wall.
  
  
  CONCLUSIONS
  The EOR follows the activation sequence both on the epicardium and endocardium. The apico-basal gradients are predominant repolarization gradients, as compared with the epicardial-endocardial gradients.
authors.affiliation: Department of Arrhythmias, Skåne University Hospital, Lund University, Lund, Sweden.
authors.forename: Ole
authors.initials: O
authors.lastname: Kongstad
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Xia
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Liang
authors.forename: Bertil
authors.initials: B
authors.lastname: Olsson
authors.forename: Shiwen
authors.initials: S
authors.lastname: Yuan
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D018780:Body Surface Potential Mapping / Q000295:instrumentation / Q000379:methods*; D004699:Endocardium / Q000502:physiology*; D006329:Heart Conduction System / Q000502:physiology*; D010496:Pericardium / Q000502:physiology*; D012044:Regression Analysis; D013552:Swine; D016276:Ventricular Function / Q000502:physiology*