Objectives To explore the mechanism of electrical remodelling and autonomic neural remodelling in acute atrial fibrillation induced by stellate ganglion.
Methods Twelve adult mongrel dogs weighing 18 to 25 kg were randomly divided into 2 groups. Control group (n = 6) underwent 6-hour rapid atial pacing only. SG group (n = 6) underwent 6-hour stellate ganglion (SG) stimulation puls rapid atial pacing. AF induction rate, AF duration, ERP, dERP and ERP rate-adaption in left atrium (LA), right atrium (RA), left superior pulmonary vein (LSPV) and left inferior pulmonary vein (LIPV) sites were measured. The density of TH, ChAT, GAP-43 positive nerve in RA and LA were detectd by immunohistochemistry staining.
Results (1) The induction rate of AF was significantly increased in SG group (P<0.05), compared with baseline. The duration of AF was significantly prolonged in SG group (P<0.05), compared with baseline. (2) In SG group, ERP was significantly shortened (P<0.05), dERP was significantly increased (P<0.05), ERP rate-adaption was significantly decreased, compared with baseline. (3) SG stimulation produced greater increase of the density of TH, ChAT, GAP-43 positive nerve than no SG stimulation (P<0.05).
Conclusions Stellate ganglion stimulation promote AF induction and prolong AF maintenance in atrial and pulmonary sites. The inhibition sympathetic nerve activation by unilateral stellate ganglionectomy can reduce the AF initiating and sustaining. Acute atrial electrical remodelling and acute autonomic neural remodeling may form a vicious cycle in which each perpetuates the other, thereby initiating and sustaining AF. This vicious cycle may help to explain how AF maintains itself in its very early stage.