title: Induction of atrial fibrillation and nerve sprouting by prolonged left atrial pacing in dogs.
abstract: The authors hypothesized that rapid electrical stimulation can induce nerve sprouting in canine atria, and that LA pacing is more effective than RA pacing in inducing sustained AF. Chronic rapid (20 Hz) LA epicardial pacing was performed in six dogs. Sustained AF (>48 hours) was induced within 23 +/- 8 days, which was much faster than that with RA endocardial pacing using the same protocol (139 +/- 84 days, P < 0.05). Nerves were identified by immunocytochemical techniques. In all dogs, growth-associated protein 43-positive (sprouting) nerve density was highest near the pacing site, and the rapid LA pacing resulted in differential nerve sprouting among the LA, left superior pulmonary vein (LSPV), interatrial septum (IAS), and RA (5521 +/- 1496, 3154 +/- 2355, 3953 +/- 1164, 1559 +/- 1077 microm2/mm2, respectively, P = 0.0032). Tyrosine hydroxylase-positive (sympathetic) nerve density were not significantly different among groups (2726 +/- 1165, 1586 +/- 558, 2156 +/- 1741, 1509 +/- 1242 microm2/mm2, respectively). The nerves were inhomogeneously distributed. LA epicardial pacing induced sustained AF much faster than RA endocardial pacing and rapid electrical stimulation can induce inhomogeneous nerve sprouting near the pacing site.
authors.affiliation: Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Akira
authors.initials: A
authors.lastname: Hamabe
authors.forename: Che-Ming
authors.initials: CM
authors.lastname: Chang
authors.forename: Shengmei
authors.initials: S
authors.lastname: Zhou
authors.forename: Chung-Chuan
authors.initials: CC
authors.lastname: Chou
authors.forename: Johnny
authors.initials: J
authors.lastname: Yi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyauchi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Okuyama
authors.forename: Michaiel C
authors.initials: MC
authors.lastname: Fishbein
authors.forename: Hrayr S
authors.initials: HS
authors.lastname: Karagueuzian
authors.forename: Lan S
authors.initials: LS
authors.lastname: Chen
authors.forename: Peng-Sheng
authors.initials: PS
authors.lastname: Chen
authors.forename: Hamabe
authors.initials: H
authors.lastname: Akira
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000209:etiology*; D001341:Autonomic Nervous System; D002304:Cardiac Pacing, Artificial; D004285:Dogs; D006325:Heart Atria / Q000294:innervation* / Q000473:pathology