犬高频起搏诱发心房颤动模型心房电活动及神经重构机制研究

Atrial electrical and neural remodeling in dogs with atrial fibrillation induced by high frequency pacing at right atrium

目的观察高频率起搏犬右房制作心房颤动(AF)模型的心房肌电和神经重构变化。方法 48只比格犬,随机平均分入A组:对照;B组:500次/分(bpm)频率起搏高右房;C组:1 000bpm频率起搏高右房;D组:右侧迷走神经干(RVNT)刺激;E组:500bpm频率起搏高右房+刺激RVNT;F组:1 000bpm频率起搏高右房+刺激RVNT。测定各组起搏12h右房的AF诱发率和维持时间、心房有效不应期(AERP)、AERP离散度(AERP)、心率变异频域分析HF/LF、RVNT和星状神经节(SG)的神经信号变化。结果随着起搏时间延长,AF的诱发率和维持时间显著增加。与A组比较,B组AF诱发率和维持时间及AERPd显著增加,但HF/LF和神经信号变化不显著。与B组比较,C组AF诱发率和维持时间显著增加,HF/LF显著减小和SG活动显著增加;与A组比较,D组的AF诱发率和维持时间、AERPd、HF/LF和RVNT神经的活动显著增加。与B组比较,E组的AF诱发率和维持时间、AERPd、HF/LF和RVNT活动显著增加。与C组比较,F组的AF诱发率和维持时间SG活动显著减少、HF/LF和RVNT活动增加。结论提示以500bpm和1 000bpm起搏高位右房,RVNT刺激以及500bpm起搏高位右房+RVNT刺激,分别可以制作心房电重构、交感神经重构、迷走神经重构以及迷走神经重构合并心房电重构的AF模型。

Objective To Observe changes of atrial electrical and neural remodeling in dogs with atrial fibrillation （AF） induced by high frequency pacing at right atrium. Methods Forty eight healthy adult Beagles were randomly divided into six groups： Group A：the controls; Group 13.. 500 bpm pacing at high right atrial（HRAP） ; Group C： 1 000 bpm pacing at HRAP; Group D： stimulation at right vagus nerve trunk（RVNTS） ; Group E： 500 bpm pacing at HRAP 4- RVNTS; Group F： 1 000 bpm pacing at HRAP ＋ RVNTS. AF inducibility and maintenance, atrial effective refractory period（AERP）, AERP dispersion （AERPd）, frequency domain analysis of heart rate variability HF/LF, neural signal change of RVNT and stellate ganglion（SG）were measured. Results AF inducibility and maintenance time increased significantly with 12 hours pacing. AF inducibility, AF maintenance time and AERPd increased significantly but HF/LF ratio was of no significant difference in group B compared with group A. In group C, AF inducibility, maintenance time and SG activity were increased significantly, while HF/LF decreased significantly compared with group B. Significant increase of HF/LF ratio and neural signal of RVNT were fund in group D when compared with group A. In group E, AF inducibility, maintenance time, AERPd, HF/LF and RVNT neural signal were all increased significantly compared with group B. Compared with group C, AF inducibility, maintenance time and SG nerve signal were significantly decreased while HF/LF ratio and RVNT nerve signal were significant increased. Conclusion AF model with atrial electrical remodeling, with sympathetic remodeling,with vagal remodeling and with vagal plus atrial electrical remodeling, can be made separately by 500 bprn pacing at HRAP, 1 000 bpm pacing at HRAP, stimulation at RVNT and 500 bpm pacing at HRAP ＋ stimulation at RVNT.