title: Role of epicardial QT intervals in the assessment of ventricular repolarisation dispersion.
abstract: The role of cardiac surface QT intervals (QTI) in assessing ventricular repolarisation dispersion was investigated in 10 pentobarbital-anesthetized, open-chest sheep. Activation-recovery interval (ARI) and QTI were measured from multiple ECGs acquired from left ventricular epicardium, before and after procainamide administration (15 mg/min i.v. for 20 min). Procainamide therapy resulted in a significant prolongation in ARI and corrected QT interval (cQTI). A correlation between QTI, cQTI and ARI was found in only one animal (r = 0.78 and 0.79 respectively, p = 0.01) before procainamide therapy. No correlation was found between pooled QTI and ARI dispersion from the 10 animals at baseline or after procainamide administration (p > 0.05). There was a moderate correlation between pooled cQTI and ARI dispersion (r = 0.69, p = 0.02) before procainamide therapy. In conclusion, epicardial QTI have no significant correlation with the duration of ventricular repolarisation. Epicardial QTI dispersion is not a useful index of repolarisation heterogeneity.
authors.affiliation: School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, Australia. lwang@csu.edu.au
authors.forename: L
authors.initials: L
authors.lastname: Wang
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D018780:Body Surface Potential Mapping / Q000379:methods*; D004562:Electrocardiography / Q000379:methods; D006329:Heart Conduction System / Q000187:drug effects / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology*; D006352:Heart Ventricles / Q000187:drug effects*; D010496:Pericardium / Q000187:drug effects* / Q000502:physiology*; D011342:Procainamide / Q000494:pharmacology*; D012756:Sheep; D016276:Ventricular Function; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology
chemical_list: D000889:Anti-Arrhythmia Agents; D011342:Procainamide