title: Electrogram-guided radiofrequency catheter ablation of atrial tissue comparison with thermometry-guide ablation: comparison with thermometry-guide ablation.
abstract: OBJECTIVE
  To characterize a new method for radiofrequency energy titration during ablation of atrial tissue based on reduction in electrogram amplitude. To compare this method with energy titration using electrode thermometry.
  
  
  BACKGROUND
  Complications associated with "anatomy-based" atrial endocardial radiofrequency ablation for suppression of atrial fibrillation may be due to flawed methods of energy titration.
  
  
  METHODS
  The effect of radiofrequency ablation on electrogram amplitude was characterized in a porcine model. A method for energy titration guided by electrogram amplitude reduction ("electrogram-guided") was developed and validated prospectively. Focal (smooth and trabeculated endocardial areas) and linear (smooth endocardial areas) ablation was performed comparing energy titration guided by amplitude reduction with electrode thermometry.
  
  
  RESULTS
  Amplitude reduction during radiofrequency application was not necessarily equal among unipolar and bipolar electrograms in the ablation region; specific patterns of reduction could be discerned, based on factors such as catheter-endocardial orientation. A criterion of >90 % reduction of unipolar and/or bipolar amplitude best predicted pathologic lesion success. Electrogram-guided focal and linear lesions in smooth areas were free of lesion complications such as endocardial charring, barotrauma, or damage to contiguous extraatrial structures. However, there was a significant incidence of insufficient lesion size, principally non-transmurality, probably due to undertitration of energy. Thermometry-guided focal and linear lesions in smooth areas were uniformly transmural but frequently evidenced complications, due to overtitration of energy. Electrogram-guided focal lesions in trabeculated areas could usually not be achieved, probably due to insufficient contact of the ablation electrode with adjacent pectinate muscles. Thermometry-guided focal lesions in trabeculated areas were smaller than electrogram-guided lesions and did not evidence complications.
  
  
  CONCLUSIONS
  Electrogram-guided lesions in smooth endocardial areas were uncomplicated but had a significant incidence of non-transmurality. Thermometry-guided lesions were uniformly transmural but were frequently complicated.
authors.affiliation: Electrophysiology Research Laboratory, Allegheny University of the Health Sciences, Philadelphia, PA, USA. schwartzmand@upmc.edu
authors.forename: D
authors.initials: D
authors.lastname: Schwartzman
authors.forename: J J
authors.initials: JJ
authors.lastname: Michele
authors.forename: C T
authors.initials: CT
authors.lastname: Trankiem
authors.forename: J F
authors.initials: JF
authors.lastname: Ren
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D004195:Disease Models, Animal; D004562:Electrocardiography; D004566:Electrodes; D004699:Endocardium / Q000601:surgery; D005260:Female; D006325:Heart Atria / Q000601:surgery; D008297:Male; D012016:Reference Values; D012680:Sensitivity and Specificity; D013552:Swine; D013696:Temperature