ObjectiveTo determine the effects of resecting the lower half of left stellate ganglion (LSG) on fast ventricular rate (VR) in persistent atrial fibrillation (AF) and its mechanism. MethodsTwelve mature healthy male beagle dogs (15–25 kg) were studied. They were randomly divided into two groups (an experimental group and a control group, 6 dogs in each group). The control group were merely performed with rapid left atrial pacing to induce persistent AF. The experimental group were disposed with rapid left atrial pacing and received resection of the lower half of LSG after the persistent AF was documented. Simultaneously the ventricular rates were monitored separately before anesthesia, after anesthesia, 30 minutes and one month after LSG resection. The forward passing effective refractory period (ERP) of the canine atrioventricular node (AVN) was also measured. ResultsEach dog was documented with persistent AF after 3–6 weeks’ left atrial pacing. After resecting the lower half of LSG for 30 minutes (the control group was only observed for 30 minutes without LSG resection), the average VR of the control group attained 144.5±4.2 beats/min, while that of the experimental group was 121.5±8.7 beats/min (P<0.001). After resecting the lower half of LSG for one month (the control group was observed for one month without LSG resection), the average VR of the control group was 139.2±5.6 beats/min, while that of the experimental group was 106.5±4.9 beats/min (P<0.001). Meantime, the forward passing ERP of AVN of the experimental group was significantly prolonged than that of the control group (265.6±7.8 ms vs. 251.1±4.6 ms, P=0.003). ConclusionResection of the lower half of LSG is efficient in reducing VR in canines with persistent AF, one of the mechanisms of which may be prolonging the forward passing ERP of AVN.