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目的 :研究心肌梗死 (MI)后心室肌神经过度增生对梗死心脏电生理的影响。方法 :30只兔随机分为 3组 ,每组 10只 ,神经生长因子 (NGF)组结扎左回旋支 ,并通过皮下置管于左侧星状神经节 ,给予NGF 4 0 0U× 30d ;陈旧性MI(OMI)组结扎冠状动脉左回旋支 ,无皮下置管 ;假手术 (Sham)组开胸但不结扎冠状动脉和皮下置管。 3个月后进行心室颤动 (室颤 )阈值测定和心外膜单相动作电位记录。结果 :NGF组的室颤阈值为 (7.0 0±1.0 4 )V ,较MI组和Sham组 [(9.16± 1.2 3)和 (13.31± 2 .12 )V]明显降低 (P <0 .0 5 ) ,OMI组和Sham组的室颤阈值间差异有统计学意义 (P <0 .0 5 )。NGF组的非梗死区的单相动作电位复极 90 %的时程 (MAPD90 )和非梗死区与梗死边缘区间的复极离散度较OMI组显著增加 (P <0 .0 5 )。结论 :MI后心室肌中神经纤维过度增生可进一步促进心肌电生理的不稳定性 ,而NGF组复极离散度的增加可能是NGF组室颤阈值进一步降低的重要原因。
Objective: To study the effect of ventricular myopathy on cardiac electrophysiology after myocardial infarction (MI). Methods: Thirty rabbits were randomly divided into three groups (10 rats in each group). NGF group was ligated with left circumflex artery and subcutaneously placed in the left stellate ganglion to give NGF40U × 30d. In the MI group, the left circumflex coronary artery was ligated without subcutaneous catheterization. Sham group was opened without coronary artery and subcutaneous catheterization. Ventricular fibrillation (VF) threshold measurements and epicardial monophasic action potentials were recorded 3 months later. Results: The ventricular fibrillation threshold in NGF group was (7.0 ± 1.04) V, which was significantly lower than that in MI group and Sham group [(9.16 ± 1.2 3) vs (13.31 ± 2.12) V] (P <0.05 ), There was a significant difference in ventricular fibrillation threshold between OMI group and Sham group (P <0.05). Compared with OMI group, the non-infarct area single-phase action potential repolarization 90% MAPD90 in non-infarction area and the non-infarction area and infarction border area were significantly increased (P <0.05). Conclusion: The hyperplasia of nerve fibers in ventricular myocytes may further promote the instability of myocardial electrophysiology. The increase of repolarization dispersion in NGF group may be the important reason for the further reduction of ventricular fibrillation threshold in NGF group.