title: Relation between impedance and electrode temperature during radiofrequency catheter ablation of accessory pathways and atrioventricular nodal reentrant tachycardia.
abstract: OBJECTIVE
  Impedance monitoring has been proposed as a method to assess the adequacy of tissue heating during catheter ablation procedures. The purpose of this study was to evaluate the relation among initial impedance, fall in impedance, and electrode temperature during catheter ablation procedures.
  
  
  RESULTS
  Data from 248 applications of radiofrequency energy in 45 consecutive patients (26 with accessory pathways and 19 with atrioventricular nodal reentrant tachycardia) referred for catheter ablation were analyzed. The initial impedance was higher during ablation of accessory pathways than during atrioventricular nodal reentrant tachycardia (116+/-66 versus 106+/-80 omega, P < .001). In both groups, a significant correlation was observed between the initial impedance and temperature (R = 0.98, P < .001). After accounting for differences between patients and ablation targets, an even closer correlation was observed (accessory pathways: R = 0.95, P < .0001; atrioventricular nodal reentrant tachycardia: R = 0.94, P < .0001).
  
  
  CONCLUSIONS
  These data suggest that monitoring of the initial impedance and the fall in impedance during ablation procedures may provide clinically valuable information to assess the efficacy of tissue heating and lesion formation.
authors.affiliation: Johns Hopkins Medical Institutions, Baltimore, MD, USA.
authors.forename: E
authors.initials: E
authors.lastname: Nsah
authors.forename: R
authors.initials: R
authors.lastname: Berger
authors.forename: L
authors.initials: L
authors.lastname: Rosenthal
authors.forename: R
authors.initials: R
authors.lastname: Hui
authors.forename: B
authors.initials: B
authors.lastname: Ramza
authors.forename: P
authors.initials: P
authors.lastname: Jumrussirikul
authors.forename: J H
authors.initials: JH
authors.lastname: Lawrence
authors.forename: G
authors.initials: G
authors.lastname: Tomaselli
authors.forename: D
authors.initials: D
authors.lastname: Kass
authors.forename: H
authors.initials: H
authors.lastname: Calkins
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017115:Catheter Ablation / Q000379:methods; D015986:Confounding Factors, Epidemiologic; D017097:Electric Impedance; D004566:Electrodes; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000601:surgery*; D013696:Temperature