title: Acute electrical isolation is a necessary but insufficient endpoint for achieving durable PV isolation: the importance of closing the visual gap.
abstract: OBJECTIVE
  Temporary, ablation-mediated effects such as oedema may cause reversible pulmonary vein (PV) isolation. To investigate this, point-by-point circumferential ablation was performed to achieve acute electrical PV isolation with an incomplete circumferential ablation line. Then, the impact of this intentional 'visual gap' (ViG) on the conduction properties of the ablation lesion set was assessed with adenosine and pacing manoeuvres.
  
  
  RESULTS
  Twenty-eight patients undergoing ablation for paroxysmal (n= 20) or persistent atrial fibrillation (n= 8) were included. Pulmonary vein (PV) ablation was performed around ipsilateral vein pairs. Once acute isolation was achieved, ablation was halted and the presence and size of the ViG were calculated. The ViG electrophysiological properties were tested with pace capture along the ViG at 10 mA/2 ms, and assessment for dormant PV conduction with adenosine. Despite electrical isolation, a ViG was present in 75% (n= 42/56) of vein pairs (21 of 28 left PVs and 21 of 28 right PVs). There was no difference in the ViG size between the left and right PVs (22.1 ± 14.2 and 17.3 ± 11.3 mm, P > 0.05). Dormant PV connections were revealed by adenosine in more than a quarter (n= 12/42) of acutely isolated PV pairs, of which the majority were dependent on conduction through the ViG.
  
  
  CONCLUSIONS
  Electrical PV isolation can usually be achieved without complete circumferential ablation. However, more than a quarter of these 'isolated' PVs exhibit dormant conduction-predominantly via the un-ablated 'ViGs' in the ablation lesion set. These findings support the hypothesis that reversible tissue injury contributes to PV isolation that may be acute but not necessarily durable.
authors.affiliation: Helmsley Electrophysiology Center,  Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1030, New York, NY 10029,  USA.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Miller
authors.forename: Andre
authors.initials: A
authors.lastname: d'Avila
authors.forename: Srinivas R
authors.initials: SR
authors.lastname: Dukkipati
authors.forename: Jacob S
authors.initials: JS
authors.lastname: Koruth
authors.forename: Juan
authors.initials: J
authors.lastname: Viles-Gonzalez
authors.forename: Craig
authors.initials: C
authors.lastname: Napolitano
authors.forename: Charles
authors.initials: C
authors.lastname: Eggert
authors.forename: Avi
authors.initials: A
authors.lastname: Fischer
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Gomes
authors.forename: Vivek Y
authors.initials: VY
authors.lastname: Reddy
mesh_terms: D000241:Adenosine; D000368:Aged; D000889:Anti-Arrhythmia Agents; D001281:Atrial Fibrillation / Q000150:complications / Q000503:physiopathology* / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D004487:Edema / Q000150:complications / Q000503:physiopathology; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D011237:Predictive Value of Tests; D011667:Pulmonary Veins / Q000502:physiology / Q000601:surgery*
chemical_list: D000889:Anti-Arrhythmia Agents; D000241:Adenosine