Impact of pharmacological autonomic blockade on complex fractionated atrial electrograms.
BACKGROUND
The influence of the autonomic nervous system on the pathogenesis of complex fractionated atrial electrograms (CFAE) during atrial fibrillation (AF) is incompletely understood. This study evaluated the impact of pharmacological autonomic blockade on CFAE characteristics.


RESULTS
Autonomic blockade was achieved with propanolol and atropine in 29 patients during AF. Three-dimensional maps of the fractionation degree were made before and after autonomic blockade using the Ensite Navx system. In 2 patients, AF terminated following autonomic blockade. In the remaining 27 patients, 20,113 electrogram samples of 5 seconds duration were collected randomly throughout the left atrium (10,054 at baseline and 10,059 after autonomic blockade). The impact of autonomic blockade on fractionation was assessed by blinded investigators and related to the type of AF and AF cycle length. Globally, CFAE as a proportion of all atrial electrogram samples were reduced after autonomic blockade: 61.6 +/- 20.3% versus 57.9 +/- 23.7%, P = 0.027. This was true/significant for paroxysmal AF (47 +/- 23% vs 40 +/- 22%, P = 0.003), but not for persistent AF (65 +/- 22% vs 62 +/- 25%, respectively, P = 0.166). Left atrial AF cycle length prolonged with autonomic blockade from 170 +/- 33 ms to 180 +/- 40 ms (P = 0.001). Fractionation decreases only in the 14 of 27 patients with a significant (>6 ms) prolongation of the AF cycle length (64 +/- 20% vs 59 +/- 24%, P = 0.027), whereas fractionation did not reduce when autonomic blockade did not affect the AF cycle length (58 +/- 21% vs 56 +/- 25%, P = 0.419).


CONCLUSIONS
Pharmacological autonomic blockade reduces CFAE in paroxysmal AF, but not persistent AF. This effect appears to be mediated by prolongation of the AF cycle length.
Service de Rythmologie, Hôpital Cardiologique du Haut-Lévêque, Université Victor Segalen Bordeaux II, Bordeaux, France. sebastien.knecht@chu-brugmann.be
Sébastien
S
Knecht
Matthew
M
Wright
Seiichiro
S
Matsuo
Isabelle
I
Nault
Nicolas
N
Lellouche
Frédéric
F
Sacher
Steven J
SJ
Kim
Dennis
D
Morgan
Valtino
V
Afonso
Miyazaki
M
Shinzuke
Mélèze
M
Hocini
Jacques
J
Clémenty
Sanjiv M
SM
Narayan
Phillipe
P
Ritter
Pierre
P
Jaïs
Michel
M
Haïssaguerre
D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage*; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology*; D001285:Atropine / Q000008:administration & dosage*; D001341:Autonomic Nervous System / Q000187:drug effects* / Q000503:physiopathology; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006325:Heart Atria / Q000294:innervation; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D018727:Muscarinic Antagonists / Q000008:administration & dosage*; D011237:Predictive Value of Tests; D011433:Propranolol / Q000008:administration & dosage*
D000319:Adrenergic beta-Antagonists; D018727:Muscarinic Antagonists; D001285:Atropine; D011433:Propranolol