title: Is 8-mm more effective than 4-mm tip electrode catheter for ablation of typical atrial flutter?
abstract: BACKGROUND
  The prospective, randomized study comparing 4- with 8-mm tip electrodes for radiofrequency linear ablation of typical atrial flutter is not available.
  
  
  RESULTS
  A total of 104 consecutive patients with typical atrial flutter were randomly assigned to undergo radiofrequency linear ablation using a 4- (Group I, n=54) or 8-mm tip electrode (Group II, n=50) catheter (temperature-control model, preset 70 degrees C). If complete bidirectional isthmus block could not be achieved after 5 pulses, the ablation catheter was changed to the other type; the maximal radiofrequency pulse number was limited to <10 pulses. Complete or incomplete isthmus conduction block was assessed by activation sequence in a multielectrode Halo catheter during low lateral right atrial and proximal coronary sinus pacing. Before shifting to the other catheter type, the 8-mm electrode catheter achieved higher complete isthmus block rate (92% versus 67%, P<0.05) with fewer pulses (2+/-1 versus 3+/-1, P<0.05), shorter procedure time (24+/-15 versus 31+/-12 minutes, P<0.05), and shorter fluoroscopic time (14+/-10 versus 23+/-15 minutes, P<0.05). After 5 failed ablation pulses, 12 (67%) of 18 patients in group I attained complete isthmus block by using an 8-mm tip catheter, but none of 4 patients in group II achieved complete block by changing to a 4-mm tip catheter.
  
  
  CONCLUSIONS
  The 8-mm tip electrodes are more effective than the standard 4-mm length electrodes in linear ablation for typical atrial flutter. This clinical benefit may be of particular value for some patients with broad and/or thick isthmus.
authors.affiliation: Division of Cardiology, Department of Medicine, National Yang-Ming University, School of Medicine, and Veterans General Hospital-Taipei, Taiwan.
authors.forename: C F
authors.initials: CF
authors.lastname: Tsai
authors.forename: C T
authors.initials: CT
authors.lastname: Tai
authors.forename: W C
authors.initials: WC
authors.lastname: Yu
authors.forename: Y J
authors.initials: YJ
authors.lastname: Chen
authors.forename: M H
authors.initials: MH
authors.lastname: Hsieh
authors.forename: C E
authors.initials: CE
authors.lastname: Chiang
authors.forename: Y A
authors.initials: YA
authors.lastname: Ding
authors.forename: M S
authors.initials: MS
authors.lastname: Chang
authors.forename: S A
authors.initials: SA
authors.lastname: Chen
mesh_terms: D000368:Aged; D001282:Atrial Flutter / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D016896:Treatment Outcome