title: Spatiotemporal electrophysiological changes in a murine ablation model.
abstract: OBJECTIVE
  High recurrence rates after complex radiofrequency ablation procedures, such as for atrial fibrillation, remain a major clinical problem. Local electrophysiological changes that occur following cardiac ablation therapy are incompletely described in the literature. The purpose of this study was to determine whether alterations in conduction velocity, action potential duration (APD), and effective refractory period resolve dynamically following cardiac ablation.
  
  
  RESULTS
  Lesions were delivered to the right ventricle of mice using a subxiphoid approach. The sham-operated control group (SHAM) received the same procedure without energy delivery. Hearts were isolated at 0, 1, 7, 30, and 60 days following the procedure and electrophysiological parameters were obtained using high-resolution optical mapping with a voltage-sensitive dye. Conduction velocity was significantly decreased at the lesion border in the 0, 7, and 30 day groups compared to SHAM. APD(70) at the lesion border was significantly increased at all time points compared to SHAM. Effective refractory period was significantly increased at the lesion border at 0, 1, 7, and 30 days but not at 60 days post-ablation. This study demonstrated that post-ablation electrophysiological changes take place immediately following energy delivery and resolve within 60 days.
  
  
  CONCLUSIONS
  Cardiac ablation causes significant electrophysiological changes both within the lesion and beyond the border zone. Late recovery of electrical conduction in individual lesions is consistent with clinical data demonstrating that arrhythmia recurrence is associated with failure to maintain bi-directional conduction block.
authors.affiliation: The Leon H. Charney Division of Cardiology,  New York University School of Medicine, 522 First Avenue, 8th Floor, Smilow Building, New York, NY 10016,  USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Bernstein
authors.forename: Srikant
authors.initials: S
authors.lastname: Duggirala
authors.forename: Michael
authors.initials: M
authors.lastname: Floberg
authors.forename: Pehr
authors.initials: P
authors.lastname: Elfvendal
authors.forename: Laura M
authors.initials: LM
authors.lastname: Kuznekoff
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Lader
authors.forename: Carolina
authors.initials: C
authors.lastname: Vasquez
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Morley
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000453:epidemiology / Q000503:physiopathology* / Q000601:surgery*; D017115:Catheter Ablation; D055724:Electrophysiological Phenomena / Q000502:physiology*; D005260:Female; D006329:Heart Conduction System / Q000502:physiology; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D012008:Recurrence