title: Prolongation of activation-recovery interval over a preexcited region before and after catheter ablation in patients with Wolff-Parkinson-White syndrome.
abstract: BACKGROUND
  Preexisting changes in repolarization properties play an important role in T wave abnormalities (cardiac memory) after ablation in patients with Wolff-Parkinson-White (WPW) syndrome. However, no report has provided direct evidence for prolongation of action potential duration (APD) over a preexcited region before and after ablation.
  
  
  RESULTS
  We studied 10 patients with ventricular preexcitation due to a left-sided accessory pathway (AP) (group M) and 12 patients with concealed left-sided AP (group C) to clarify prolongation of APD using activation-recovery intervals (ARIs) from epicardial and endocardial unipolar electrograms in patients with WPW syndrome. ARI was calculated from unipolar electrograms at the His bundle and the coronary sinus adjacent to the AP during atrial pacing (100 beats/min) before and 30 minutes after ablation. Before ablation, ARIs at the AP site were significantly longer in group M than in group C (255+/-21 msec vs 211+/-24 msec; P < 0.01), whereas ARIs at the His bundle did not differ between the two groups (255+/-20 msec vs 245+/-27 msec; P = NS). After ablation, group M showed no significant changes in ARIs at the AP and His bundle (256+/-19 msec and 253+/-15 msec) compared with before ablation.
  
  
  CONCLUSIONS
  We found by direct analysis of ARIs from the epicardium that APD prolongation over the preexcited region was present before catheter ablation and persisted after catheter ablation. The gradual changes in repolarization properties, including APD prolongation after discontinuation of AP, may be one mechanism of cardiac memory after catheter ablation in patients with WPW syndrome.
authors.affiliation: First Department of Internal Medicine, University of Nagoya School of Medicine, Japan. inden@med.nagoya-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Inden
authors.forename: M
authors.initials: M
authors.lastname: Hirai
authors.forename: Y
authors.initials: Y
authors.lastname: Takada
authors.forename: A
authors.initials: A
authors.lastname: Shimizu
authors.forename: K
authors.initials: K
authors.lastname: Shimokata
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshida
authors.forename: M
authors.initials: M
authors.lastname: Akahoshi
authors.forename: T
authors.initials: T
authors.lastname: Kondo
authors.forename: H
authors.initials: H
authors.lastname: Saito
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000368:Aged; D018780:Body Surface Potential Mapping; D002036:Bundle of His / Q000503:physiopathology; D017115:Catheter Ablation; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function / Q000502:physiology*; D013997:Time Factors; D014927:Wolff-Parkinson-White Syndrome / Q000601:surgery*