摘要
目的研究心室壁中层(M层)起搏对缺血再灌注犬跨壁复极离散(TDR)的影响,探讨采用M层起搏技术防治TDR增大相关性心律失常的可行性。方法制作正常犬及缺血再灌注后犬左室楔形心肌组织块模型,观察心内、外膜及M层起搏时,各层心肌动作电位时程(APD)及TDR的变化。结果心室内、外膜和M层起搏,心肌各层APD无显著变化(P﹥0.05);在正常状态时,心外膜起搏时,心外膜与M层之间的传导时间(TM-Epi)(24.3±2.4ms)显著长于心内膜起搏(12.0±0.8 ms)或M层起搏(12.6±0.7 ms)时的TM-Epi(P﹤0.05)。M层起搏时,TDR较外膜起搏明显减小(34.9±5.4 ms vs 71.5±6.1 ms,P﹤0.01),与内膜起搏(35.9±5.4 ms)相比无显著差异(P﹥0.05)。缺血再灌注后,结果与正常状态时相似。心外膜起搏(32.3±5.8 ms)时,TM-Epi较M层起搏(15.1±2.9ms)或内膜起搏(15.3±2.8 ms)进一步延长(P﹤0.05)。M层起搏时,TDR较外膜起搏明显减小(63.3±13.3 msvs 111.1±17.7 ms,P﹤0.01),与内膜起搏(62.8±13.8 ms)相比无显著差异(P﹥0.05)。结论与心外膜起搏相比,M层起搏可有效减小TDR;但与心内膜起搏相比,无明显差别。
Objective To investigate the effcts of pacing at left ventricular（LV） mid-myocardium （M） on transmural dispersion of repolarization（TDR） in iscbemia-reperfusion. Methods A transmural ECG and transmembrane action po- tentials were simultaneously recorded from epicardial（Epi） , M, and endocardial（Endo） cells of arterially perfused canine LV wedge preparations in normal and after isehemia-reperfusion, paced at Epi, M, and Endo layer respectively. Action po- tential duration （APD） and the TDR were observed. Results There were no significant change in APD of Epi, M, and Endo pacing （P 〉 0.05 ）. However, the conduction time from M to Epi （ TM_Epi ） increased when the pacing site shifted from Endo （12.0 ± 0.8 ms） to Epi （24.3 ± 2.4 ms） （P 〈 0.05 ）, but did not increase when pacing shifted from Endo to M （12.6 ± 0.7 ms） （P 〉 0.05 ） in normal state. When the M layer was being paced, TDR decreased compared with the Epi pacing（34.9 ± 5.4 ms vs 71.5 ±6.1 ms ,P 〈 0.01 ）. But it was not significantly different from Endo pacing（35.9 ±5.4 ms ,P 〉 0.05 ）. The result was proved again in ischemia-reperfusion experiments. A shift from Endo （15.3 ± 2.8 ms） or M （ 15.1 ± 2.9 ms） to Epi pacing （ 32.3 ± 5.8 ms） caused a further prolongation of T_M-Epi （ P 〈 0.05 ）. TDR were initially augmented during Epi pacing （111. 1 ± 17.7 ms） compared with Endo pacing （62.8 ±13.8 ms） or M pacing （63.3± 13.3 ms）. However, no significant difference was observed in TDR between Endo pacing and M pacing （P 〉 0. 05 ）. Conclusion LV mid-myocardial pacing can reduce the TDR compared with Epi pacing, which is not significantly changed compared with Endo pacing.
出处
《中国心脏起搏与心电生理杂志》
2012年第6期516-519,共4页
Chinese Journal of Cardiac Pacing and Electrophysiology
基金
国家自然基金项目(项目编号:30971230)
关键词
电生理学
跨室壁复极离散
M层起搏
缺血再灌注
动作电位时程
Electrophysiology
Transmural dispersion ofrepolarization
Mid- myocardial pacing
Ischemia-reperfusion
Ac-tion potential duration
