靶向损毁心交感神经元对犬心肌梗死后心室电生理性质的影响

Effects of targeted ablation of cardiac sympathetic neurons on ventricular electrophysiological properties in dogs with chronic myocardial infarction

目的探讨靶向损毁心交感神经元（targeted ablation of cardiac sympathetic neurons，TACSN）对心肌梗死（MI）后心室电生理性质的影响。方法使用随机数字表法将38只成年雄性杂种犬随机分为：假手术组（8只）、MI组（15只）、MI＋TACSN组（15只）。通过微导管在前降支内注射明胶海绵颗粒栓塞剂构建MI模型。MI＋TACSN组在术后1周进行左侧星状神经节（LSG）内注射霍乱毒素B亚单位（CTB）与肥皂草素（SAP）的轭合物CTB-SAP损毁心交感神经元。术后5周，测量各组犬梗死周边区、正常区、左心室基底部、右心室心尖部、右心室中部及右心室基底部的有效不应期（ERP）、动作电位时限（APD）、APD回复性质、ADP交替周长。结果与MI组相比TACSN显著延长MI后QTc间期[（387．13±16．29）ins对（361．58±23．65）ms，P〈0．05J，减少Tpeak-Tend（51．38±7．41）ins对（66．75±7．97）ms，P〈0．05]，改善心率变异性；延长心室各个部位ERP、动作电位复极完成90％所需时间（APDgo），减少其离散度（0．040±0．019对0．077±0．025，P〈0．05；0．031±0．012对0．062±0．015，P〈0．05）；降低梗死周边区APD回复曲线的最大斜率（Smax），减少其离散度（0．071±0．022对0224±0．079，P〈0．05）；降低梗死同边区APD交替周长。结论TACSN显著改善MI后心室电生理牲质，可能是防治MI后恶性室性心律失常的新策略。

Objective To investigate the effects of targeted ablation of cardiac sympathetic neurons （ TACSN ） on ventricular electrophysiological properties after myocardial infarction （ MI ）. Methods Thirtyeight adult mongrel male dogs were randomly divided into three groups by means of radom number table ： Sham group （ n=8 ）, MI group （ n=15 ）, and MI＋TACSN group （ n=15 ）. The MI model was established by intravascular injection of gelatin sponge particles into left anterior descending coronary artery. After 1 week of the MI surgery, CTB-SAP was injected into the left stellate ganglion （ LSG ） of MI ＋ TACSN group to destroy the cardiac sympathetic neurons. After 5 weeks of MI surgery, effective refractory period （ ERP ）, action potential duration （ APD ）, APD restitution property and APD ahernans cycle length were measured at the infarct border zone, remote area, left ventricular base, right ventricular apex, median area of right ventricle, and right ventricular base of all three groups. Results Compared with MI group, TACSN significantly prolonged QTc interval [ （ 387.13± 16.29 ） ms vs. （ 361.58 ±23.65 ） ms, P〈0.05 ], reduced Tpeak-Tend [ （ 51.38 ± 7.41 ） ms vs. （ 66.75 ± 7.97 ） ms, P〈0.05 ], impreved HRV, prolonged ERP and APD90, reduced the dispersion of ERP and APD90 （ 0.040 ± 0.019 vs. 0.077 ± 0.025, P〈0.05; 0.031±0.012 vs. 0.062 ± 0.015, P〈0.05 ）, reduced the maximal slope （ Smax ） of APD restitution curve and APD alternans cycle length of the infarct border zone, and reduced the dispersion of Smax （ 0.071 ±0.022 vs. 0.224± 0.079, P〈0.05 ） Conclusion TACSN significantly improved ventricular electrophysiological properties after MI, which may be a novel strategy for the prevention and treatment of malignant ventricular arrhythmias after MI.