中文摘要：

目的研究心室M层起搏对犬跨室壁复极离散（TDR）的影响，探讨采用心室M层起搏技术防治跨室壁复极离散增大相关性心律失常的可行性。方法制作犬左心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限（APD）及TDR的变化。结果分别行心室肌内、外膜和M层起搏，心肌各层APD差异无统计学意义（P〉0．05）；但M层起搏时，TDR较外膜起搏明显减小[（34．9±5．4）ms对（71．5±6．1）ms，P〈0．01]；与内膜起搏相比差异无统计学意义[（34．9±5．4）ms对（35．9±5．4）ms，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，差异无统计学意义。

英文摘要：

Objective The Purpose of this study was to investigate the effects of pacing in left ventric- ular mid-myocardium on transmural dispersion of repolarization （TDR）. This study would provide experimental evidence for prevention and treatment of arrhythmias which were related with amplification of TDR. Methods Atransmural ECG and transmembrane action potentials were simultaneously recorded from epicardial, mid-myo- cardium（ M）, and endocardial cells of arterially perfused canine LV wedge preparations, paced at epicardial, M, and endocardial layer respectively. Action potential duration （APD） and the TDR were observed. Results APD no significantly changed in epicardial, M, and endocardial pacing（P〉0. 05 ）. When mid-myocar- dial pacing,TDR decreased compared with the epicardial pacing, [ （34. 9±5.4） ms vs. （71.5±6. 1 ） ms,P〈 0. 011. But it was no significantly different fromendocardial pacing [ （34. 9±5.4 ）ms vs. （35.9 ±5.4 ）ms, P〉 0. 051. Conclusion LV mid-myocardial pacing can reduce the TDR compared with epicardial pacing, which was no significant changed compared with endocardial pacing.