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

Objective To investigate the effects of targeted ablation of cardiac sympathetic neurons (TACSN) on ventricular electrophysiological properties after myocardial infarction (MI) . Methods Thirty-eight 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 alternans 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 APDrestitution curve and APD alternans cycle length of the infarct border zone, and reduced thedispersion 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. Key words: Targeted ablation of cardiac sympathetic neurons; Myocardial infarction; Action potential duration; Effective refractory period