Prolonged rapid right atrial pacing significantly shortened the effective refractory period of the LSPV-LA junction compared to controls (83.33 vs 111.67 ms, P<0.05) and increased autonomic nerves.
Does prolonged rapid atrial pacing induce autonomic neural remodeling at the PV-LA junction in a canine model?
Prolonged rapid atrial pacing induces autonomic neural remodeling at the PV-LA junction, which may contribute to the initiation of atrial fibrillation.
Absolute Event Rate: 83.33% vs 111.67%
p-value: p=< 0.05
Background No evidence has been presented to show whether autonomic neural remodeling occurs in pulmonary vein‐left atrium (PV‐LA) junction and what an important role it may play in AF. This study aims to find out these issues in a prolonged rapid atrial pacing canine model. Methods Twelve healthy mongrel dogs were randomly divided into two groups, six in each: the paced group underwent rapid right atrial pacing at 400 beats per minute for 4 weeks, and the control group was not paced. The effective refractory period (ERP) of left superior pulmonary vein‐left atrium (LSPV‐LA) junction in all animals was determined immediately after 4 weeks. Tissues were removed from 1 cm around all PV‐LA junctions. Immunohistochemical staining and western blotting were performed to examine the expression of tyrosine hydroxylase (TH) and choline acetyltransferase (ChAT). Results Compared with the control group, ERP of LSPV‐LA junction of the paced group was significantly shortened (83.33 ± 16.33 ms vs 111.67 ± 20.41 ms, P < 0.05). Spontaneous atrial fibrillation developed in two animals in the paced group, but in none of the control group. Immunohistochemistry showed that the average density and heterogeneity of both TH‐ and ChAT‐positive nerves at LSPV‐LA junction in the paced group were significantly higher compared to the control group (P < 0.01). Western blotting showed that the expression of TH and ChAT at four PV‐LA junctions in the paced group also increased markedly compared with the control group (P < 0.01). Conclusion Autonomic neural remodeling did exist in PV‐LA junction after prolonged atrial pacing, which may contribute to the initiation of atrial fibrillation and be significant in its treatment by radiofrequency catheter ablation.
Zheng et al. (Fri,) conducted a other in Atrial fibrillation (canine model) (n=12). Rapid right atrial pacing vs. No pacing was evaluated on Effective refractory period (ERP) of left superior pulmonary vein-left atrium (LSPV-LA) junction (p=< 0.05). Prolonged rapid right atrial pacing significantly shortened the effective refractory period of the LSPV-LA junction compared to controls (83.33 vs 111.67 ms, P<0.05) and increased autonomic nerves.