title: A prospective randomized comparison of direct current and radiofrequency ablation of the atrioventricular junction.
abstract: OBJECTIVE
  The purpose of this study was to compare direct current and radiofrequency ablation of the atrioventricular (AV) junction in a prospective randomized fashion.
  
  
  BACKGROUND
  Catheter ablation of the AV junction can be performed using either direct current shocks or radiofrequency energy. To date, these two techniques have never been compared prospectively or in a randomized study.
  
  
  METHODS
  Forty patients with drug-refractory uncontrolled atrial fibrillation-flutter (38 patients) or inappropriate sinus tachycardia (2 patients) were randomly assigned to undergo direct current ablation (20 patients) using up to four shocks of 200 to 300 J or radiofrequency ablation (20 patients) using up to 15 applications of 16 to 25 W for 30 s. If complete AV block was not successfully induced, the ablation procedure was repeated using the alternate type of energy. A rate-responsive ventricular pacemaker was implanted in each patient. The intrinsic escape rhythm was evaluated 15 min, 2 days and 3, 6 and 12 months after ablation.
  
  
  RESULTS
  Persistent complete AV block was successfully induced during the first ablation session in 13 (65%) of 20 patients randomly assigned to undergo direct current ablation, compared with 19 (95%) of 20 patients randomly assigned to undergo radiofrequency ablation (p < 0.05). Each patient whose first ablation attempt failed had a successful outcome with the alternate type of energy. The overall efficacy of radiofrequency ablation (26 [96%] of 27 patients) was significantly greater than that of direct current ablation (14 [67%] of 21 patients, p < 0.01). The duration of the direct current and radiofrequency ablation sessions did not differ significantly. The mean peak plasma creatine kinase MB fraction concentration was significantly higher after direct current ablation (58 +/- 29 IU/liter) than after radiofrequency ablation (2 +/- 2 IU/liter) (p < 0.001). An escape rhythm was present 15 min after ablation in an equal proportion of patients undergoing direct current and radiofrequency ablation (78% and 85%, respectively, p = 0.6). An escape rhythm was present in all patients 3, 6 and 12 months after ablation. The mean escape rhythm cycle length 15 min after direct current ablation (2,074 +/- 677 ms) was significantly longer than that 15 min after radiofrequency ablation (1,460 +/- 294 ms) (p < 0.05); however, the mean escape rhythm cycle lengths did not differ significantly at 2 days or 3, 6 or 12 months after ablation. Immediate arrhythmic complications did not occur after either procedure. One patient died suddenly 6.5 months after direct current ablation.
  
  
  CONCLUSIONS
  Radiofrequency ablation of the AV junction is more efficacious and safer than direct current ablation and should be the preferred method for inducing complete AV block in patients who are appropriate candidates for ablation of AV conduction.
authors.affiliation: Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0022.
authors.forename: F
authors.initials: F
authors.lastname: Morady
authors.forename: H
authors.initials: H
authors.lastname: Calkins
authors.forename: J J
authors.initials: JJ
authors.lastname: Langberg
authors.forename: W F
authors.initials: WF
authors.lastname: Armstrong
authors.forename: M
authors.initials: M
authors.lastname: de Buitleir
authors.forename: R
authors.initials: R
authors.lastname: el-Atassi
authors.forename: S J
authors.initials: SJ
authors.lastname: Kalbfleisch
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000453:epidemiology / Q000401:mortality / Q000601:surgery; D001283:Atrioventricular Node / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D016757:Death, Sudden, Cardiac / Q000453:epidemiology; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006331:Heart Diseases / Q000150:complications / Q000453:epidemiology / Q000401:mortality / Q000601:surgery; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D011446:Prospective Studies; D012008:Recurrence; D013997:Time Factors