Cardioprotective effects of right stellate ganglion block combined with dexmedetomidine in rats with atrial fibrillation-like atrial tachyarrhythmia

OBJECTIVE: To evaluate right stellate ganglion block (SGB) plus dexmedetomidine (Dex) in a rat model of atrial fibrillation-like (AF-like) atrial tachyarrhythmia. METHODS: Male Sprague-Dawley rats were assigned to Sham, AF, AF+amiodarone, AF + SGB and AF + SGB+Dex groups. AF-like atrial tachyarrhythmia was induced by daily CaCl₂-acetylcholine injections for 7 days, and interventions were administered 1 h before modelling. ECG, echocardiography, electrophysiology, histology, ELISA, Western blot/qPCR, immunofluorescence and electron microscopy were performed. RESULTS: Compared with the AF group, SGB + Dex reduced arrhythmia duration (5.0 ± 1.5 vs. 16.3 ± 2.5 s, p < 0.001) and ventricular rate (344.3 ± 19.9 vs. 398.1 ± 19.2 bpm, p = 0.004), preserved LVEF (83.3% ± 9.2% vs. 72.2% ± 6.7%, p = 0.032), attenuated left atrial enlargement and fibrosis, partially reversed effective refractory period shortening, reduced inducibility, decreased collagen I/III, TGF-β1 and TNF-α, and altered SK2 expression in the stellate ganglion. Direct SGB versus SGB + Dex comparisons were not statistically significant across most major endpoints. CONCLUSION: Right SGB + Dex was associated with attenuation of electrical and structural remodelling in this AF-like atrial tachyarrhythmia model. These findings support a protective SGB-based strategy but remain associative. Because no Dex-only group was included, the independent contribution of Dex and the incremental benefit of adding Dex to SGB require further investigation.