title: Electrochemical potentials during radiofrequency energy delivery: a new method to control catheter ablation of arrhythmias.
abstract: OBJECTIVE
  Thermal injury of subendocardial tissue leads to a release of electrolytes and free radicals from the intracellular site creating a change in electrochemical potential (eP) between the distal and the proximal catheter tip electrodes. The aim of the study was to verify the detection of ablation-induced release of electrolytes and free radicals and to assess the suitability of control-line energy delivery at ablation by measuring eP.
  
  
  RESULTS
  In vitro tests under constant flow conditions were performed in a 101 bath of physiological saline solution or bovine blood. Endomyocardial preparations of fresh bovine hearts were used. Closed-loop temperature-controlled, irrigated and closed-loop eP-controlled ablations were performed. In vivo animal investigations were performed in six anaesthetized and ventilated pigs. The existence of the eP was established in the tank model and was confirmed in animal investigations. High correlations were found between eP and catheter tip temperature (r=0.87) and between maximum eP and induced lesion size (r=0.85). Also a high correlation (r=0.85, P<0.001) was found between eP and lesion volume.
  
  
  CONCLUSIONS
  Control of energy delivery during RF ablation by the measurement of eP is feasible. In comparison with temperature controlled RF ablation, ablation guided by eP-measurement revealed a superior correlation with induced lesion size. Especially during cooled radiofrequency catheter ablation eP is the only parameter for control of energy delivery.
authors.affiliation: Kerckhoff-Heart Center, Department of Cardiology, Bad Nauheim, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Erdogan
authors.forename: J
authors.initials: J
authors.lastname: Carlsson
authors.forename: S
authors.initials: S
authors.lastname: Grumbrecht
authors.forename: S
authors.initials: S
authors.lastname: Kostin
authors.forename: B
authors.initials: B
authors.lastname: Schulte
authors.forename: M
authors.initials: M
authors.lastname: Schlapp
authors.forename: J
authors.initials: J
authors.lastname: Neuzner
authors.forename: H F
authors.initials: HF
authors.lastname: Pitschner
mesh_terms: D000200:Action Potentials; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000517:prevention & control / Q000601:surgery; D017115:Catheter Ablation / Q000295:instrumentation; D002417:Cattle; D004563:Electrochemistry; D004567:Electrodes, Implanted; D004573:Electrolytes / Q000528:radiation effects*; D005609:Free Radicals / Q000528:radiation effects*; D006321:Heart / Q000528:radiation effects; D018499:Linear Energy Transfer / Q000528:radiation effects*; D023421:Models, Animal; D008955:Models, Cardiovascular; D011237:Predictive Value of Tests; D013552:Swine; D014835:Volatilization / Q000528:radiation effects
chemical_list: D004573:Electrolytes; D005609:Free Radicals