title: Time course of adenosine-induced pulmonary vein reconnection after isolation: implications for mechanism of dormant conduction.
abstract: BACKGROUND
  Adenosine (ADO) has been proposed to reconnect isolated pulmonary veins (PVs) postablation through hyperpolarization of damaged myocytes in an animal model. However, PV reconnection can occur via ADO-mediated sympathetic activation. We sought to determine the mechanism of ADO-induced PV reconnection in the clinical setting by characterizing its time course and location in patients undergoing PV isolation.
  
  
  METHODS
  Seventy-four patients (61 male; age 61 ± 10 years) undergoing PV isolation for atrial fibrillation (54 [73%] paroxysmal and 19 [27%] persistent) were studied. After each PV was isolated, a 12-mg intravenous bolus of ADO was administered and onset, offset, and location of ADO-induced PV reconnection and onset and offset of bradycardia were analyzed.
  
  
  RESULTS
  In 22 (30%) patients, ADO-induced PV reconnection occurred in 34 of 270 (13%) PVs. In 24 (71%) PVs, the duration of ADO-induced reconnection exceeded that of bradycardia. The onset of ADO-induced reconnection occurred before the onset of bradycardia in 10 (30%) PVs and during bradycardia in 23 (70%) PVs. No PVs exhibited onset of reconnection after resolution of bradycardia. Common sites of PV reconnection included the carinal region (41% of right PVs and 29% of left PVs) and left PV-atrial appendageal ridge region (35% of left PVs).
  
  
  CONCLUSIONS
  ADO-induced PV reconnection occurs during the bradycardic phase of the ADO bolus response and not during the late tachycardic phase. ADO-induced PV dormant conduction is closely associated with the negative dromotropic effects of ADO and suggests that hyperpolarization of the resting membrane is the unifying mechanism.
authors.affiliation: Department of Medicine, Division of Cardiology, Cornell University Medical Center, New York, New York 10021, USA. jac9029@med.cornell.edu
authors.forename: Jim W
authors.initials: JW
authors.lastname: Cheung
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Chung
authors.forename: James E
authors.initials: JE
authors.lastname: Ip
authors.forename: Steven M
authors.initials: SM
authors.lastname: Markowitz
authors.forename: Christopher F
authors.initials: CF
authors.lastname: Liu
authors.forename: George
authors.initials: G
authors.lastname: Thomas
authors.forename: Bruce B
authors.initials: BB
authors.lastname: Lerman
mesh_terms: D000241:Adenosine; D000889:Anti-Arrhythmia Agents; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology; D017115:Catheter Ablation; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000187:drug effects* / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents; D000241:Adenosine