Adenosine restores atrio-venous conduction after apparently successful ostial isolation of the pulmonary veins.
OBJECTIVE
Pulmonary vein (PV) isolation is a curative treatment for patients with atrial fibrillation. The aim of this study was to evaluate prospectively the effects of adenosine administration on the PV activity and atrio-venous conduction after PV isolation.


RESULTS
Twenty-nine patients (21 m; age: 55+/-8 years) were submitted to ostial PV isolation guided by basket catheter recordings. After successful isolation, the effects of a 12 mg intravenous bolus of adenosine were tested in 62 PVs. In 22/62 PVs (35%), left atrium (LA)-to-PV conduction was transiently (16.6+/-7.1 s, range: 3.8-27.9 s) or permanently (3 PVs) restored in response to adenosine administration. The prevalence of this phenomenon was 39% in left superior PVs, 43% in right superior PVs, and 22% in left inferior PVs (p=0.365). It occurred more frequently in the presence of dissociated PV activity (11/15 PVs, 73% vs. 11/47 PVs, 23%; p=0.002), whereas it was not influenced by the median duration of the radiofrequency current (RFC) delivery for each PV [19 (IQR: 12-26) min vs. 16 (IQR: 11-24) min: p=0.636]. A lengthening or shortening of the LA-PV conduction time was observed at LA-PV conduction appearance and disappearance in 36% and 55% of the cases, respectively. Further RFC applications (median: 5.5 min, IQR: 4-11 min) at the residual conduction breakthrough(s) indicated by the basket catheter recordings definitively eliminated adenosine-induced recovery of LA-PV conduction in all cases. Finally, when present, intrinsic PV discharge was invariably depressed by adenosine administration.


CONCLUSIONS
Adenosine may transiently or permanently re-establish LA-PV conduction after apparently successful PV isolation. This phenomenon is abolished by additional RFC delivery. However, its possible influence on the clinical results of PV ablation must be evaluated by properly designed, randomized studies.
Tritto
Massimo
M
Cardiology Department Mater Domini, via Gerenzano, 2, 21053 Castellanza, VA, Italy. m.tritto@libero.it
De Ponti
Roberto
R
Salerno-Uriarte
Jorge A
JA
Spadacini
Giammario
G
Marazzi
Raffaella
R
Moretti
Paolo
P
Lanzotti
Marcelo
M
D000241:Adenosine / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000601:surgery; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011667:Pulmonary Veins / Q000601:surgery*; D016896:Treatment Outcome
D000889:Anti-Arrhythmia Agents; D000241:Adenosine