title: Randomized comparison of two techniques for titrating power during radiofrequency ablation of accessory pathways.
abstract: BACKGROUND
  The purpose of this study was to prospectively compare the value of impedance and temperature monitoring during accessory pathway ablation. Temperature and impedance monitoring can be used during radiofrequency ablation of accessory pathways to titrate power to achieve adequate but not excessive tissue heating.
  
  
  RESULTS
  One hundred thirty-two patients with a single accessory pathway were randomly assigned to undergo ablation using either impedance monitoring or temperature monitoring. During impedance monitoring, the endpoint for titration of power was a 5- to 10-omega decrease in the measured impedance while for temperature monitoring the endpoint was to achieve a temperature of 58 degrees to 62 degrees C. Two protocols were used. In protocol 1 (90 patients), impedance monitoring was performed with a nonthermistor catheter and temperature monitoring was performed with a thermistor catheter. In protocol 2 (42 patients), a thermistor catheter was used in all patients. In protocol 1, the success rate (93% vs 93%; P = 1.0), ablation procedure duration (57 +/- 56 vs 41 +/- 41 min), fluoroscopy time (48 +/- 29 vs 41 +/- 23 min; P = 0.3), number of applications (6.2 +/- 4.7 vs 5.7 +/- 4.6; P = 0.8), and the number of applications associated with coagulum formation (0.1 +/- 0.3 vs 0.3 +/- 0.6; P = 0.1) were similar in the two groups. In protocol 2, as in protocol 1, there were no differences in the success rate (91% vs 95%; P = 1.0), ablation procedure duration (49 +/- 37 vs 62 +/- 55 min; P = 0.4), fluoroscopy time (46 +/- 24 vs 49 +/- 36 min; P = 0.8), number of applications (6.8 +/- 7.0 vs 7.8 +/- 12.1; P = 0.7), or number of applications associated with coagulum formation (0.3 +/- 0.6 vs 0.2 +/- 0.7; P = 0.6), between the impedance and temperature monitoring groups.
  
  
  CONCLUSIONS
  Temperature and impedance monitoring are equally effective in optimizing the results of accessory pathway ablation.
authors.affiliation: Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0022, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Strickberger
authors.forename: R
authors.initials: R
authors.lastname: Weiss
authors.forename: B P
authors.initials: BP
authors.lastname: Knight
authors.forename: M
authors.initials: M
authors.lastname: Bahu
authors.forename: F
authors.initials: F
authors.lastname: Bogun
authors.forename: K
authors.initials: K
authors.lastname: Brinkman
authors.forename: M
authors.initials: M
authors.lastname: Harvey
authors.forename: R
authors.initials: R
authors.lastname: Goyal
authors.forename: E
authors.initials: E
authors.lastname: Daoud
authors.forename: K C
authors.initials: KC
authors.lastname: Man
authors.forename: F
authors.initials: F
authors.lastname: Morady
mesh_terms: D000328:Adult; D001283:Atrioventricular Node / Q000503:physiopathology / Q000601:surgery*; D001823:Body Composition; D001831:Body Temperature / Q000502:physiology; D017115:Catheter Ablation; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D016343:Monitoring, Intraoperative; D011446:Prospective Studies; D014927:Wolff-Parkinson-White Syndrome / Q000503:physiopathology / Q000601:surgery*