title: Acute effect of circumferential pulmonary vein isolation on left atrial substrate.
abstract: BACKGROUND
  The left atrial (LA) substrate plays an important role in the maintenance of atrial fibrillation (AF). However, little is known about the acute effect of circumferential pulmonary vein isolation (CPVI). This study was to investigate the acute change of LA activation, voltage and P wave in surface electrocardiogram (ECG) after CPVI.
  
  
  RESULTS
  Electroanatomic mapping (NavX) was performed in 50 patients with AF (mean age = 54 +/- 10 years, 36 males) who underwent only CPVI. The mean peak-to-peak bipolar voltage and total activation time of LA were obtained during sinus rhythm before and immediately after CPVI. The average duration and amplitude of P waves in 12-lead ECG were also analyzed before and after CPVI. Change in the earliest LA breakthrough sites could cause decreased LA total activation time. Downward shift in the breakthrough site was inversely proportional to the proximity of the breakthrough site to the radiofrequency lesions. A shortening of P-wave duration and decrease in voltage after CPVI were observed after CPVI. Patients with recurrent AF had less voltage reduction in the atrial wall 1 cm from the circumferential PV lesions compared with those without recurrent AF (60.1 +/- 11.7% vs 74.1 +/- 6.6%, P = 0.002). Reduction of voltage < or = 64.4% in this area after CPVI is related with recurrent AF.
  
  
  CONCLUSIONS
  CPVI could result in acute change of LA substrate, involving LA activation and voltage. Less reduction of voltage in the atrial wall adjacent to the circumferential PV lesions after CPVI may be associated to the recurrence of AF.
authors.affiliation: Department of Medicine and Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan.
authors.forename: Ameya R
authors.initials: AR
authors.lastname: Udyavar
authors.forename: Sung-Hao
authors.initials: SH
authors.lastname: Huang
authors.forename: Shih-Lin
authors.initials: SL
authors.lastname: Chang
authors.forename: Yenn-Jiang
authors.initials: YJ
authors.lastname: Lin
authors.forename: Ching-Tai
authors.initials: CT
authors.lastname: Tai
authors.forename: Li-Wei
authors.initials: LW
authors.lastname: Lo
authors.forename: Ta-Chuan
authors.initials: TC
authors.lastname: Tuan
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Hu
authors.forename: Wanwarang
authors.initials: W
authors.lastname: Wongcharoen
authors.forename: Hsuan-Ming
authors.initials: HM
authors.lastname: Tsao
authors.forename: Satoshi
authors.initials: S
authors.lastname: Higa
authors.forename: Shih-Ann
authors.initials: SA
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D012008:Recurrence; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome