title: Activation recovery time measurements in evaluation of global sequence and dispersion of ventricular repolarization.
abstract: BACKGROUND
  Activation recovery time (ART), defined as the time from the earliest ventricular activation time to the end of T wave on unipolar electrograms, has been used as an index of myocardial repolarization time. However, it is unknown whether the ART can be used to estimate the global sequence and dispersion of ventricular repolarization as determined by the monophasic action potential (MAP) mapping technique.
  
  
  RESULTS
  Endocardial MAPs and unipolar electrograms were simultaneously recorded using the CARTO system from 34 +/- 12 left (n = 6) or right (n = 9) ventricular sites in 12 patients. End-of-repolarization (EOR) times from the MAPs and ARTs from the unipolar electrograms were calculated, based on which 15 sets of 3-dimensional maps of global EOR sequence and ART sequence were reconstructed. The ART sequence was consistent with the EOR sequence in 14 of 15 maps. In the 473 paired measurements obtained, the differences between the ART and the EOR time were 2 +/- 22 milliseconds (NS). A significant positive correlation between the ART and the EOR time was found in all the maps (r = 0.58 +/- 0.22). Agreement analyses showed that the differences between these 2 measurements were almost all within the range of mean difference +/- 2 SD for each individual map and for all the 473 recordings. The global dispersion of ART was 79 +/- 35 milliseconds, as compared with that of EOR time of 78 +/- 35 milliseconds (NS).
  
  
  CONCLUSIONS
  The ART from unipolar electrograms is a good estimate of EOR time measured from MAPs, suggesting the usefulness of the former in evaluation of global sequence and dispersion of ventricular repolarization.
authors.affiliation: Department of Cardiology, University Hospital, S-221 85 Lund, Sweden.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Xia
authors.forename: Ole
authors.initials: O
authors.lastname: Kongstad
authors.forename: Eva
authors.initials: E
authors.lastname: Hertervig
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Magnus
authors.initials: M
authors.lastname: Holm
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*; D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation / Q000295:instrumentation; D004562:Electrocardiography / Q000145:classification; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D013617:Tachycardia, Supraventricular / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000503:physiopathology; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000503:physiopathology; D016276:Ventricular Function