Wang L P, Jiang L M, Wang S J, Wu S J, Huang Z Q, Shan P R, Huang W J, Su L
Department of Cardiology, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China.
Department of Cardiology, Sir Run Run Shaw Hospital, Affiliated Hospital of Medical School of Zhejiang University, Shaoxing 312399, China.
Zhonghua Xin Xue Guan Bing Za Zhi. 2023 Nov 24;51(11):1175-1180. doi: 10.3760/cma.j.cn112148-20231007-00208.
Explore the relationship between tip of the left bundle branch pacing lead and anatomic location of left bundle branch as well as the mechanism of left bundle branch current of injury. To clarify the clinical value of left bundle branch current of injury during operation. The pacing leads were implanted in the hearts of two living swines. Intraoperative electrophysiological study confirmed that the left bundle branch or only the deep left ventricular septum was captured at low output. Immediately after operation, the gross specimen of swine hearts was stained with iodine to observe the gross distribution of His-purkinje conduction system on the left ventricular endocardium and its relationship with the leads. Subsequently, the swine hearts were fixed with formalin solution, and the pacing leads were removed after the positions were marked. The swine hearts were then sectioned and stained with Masson and Goldner trichrome, and the relationship between the anatomic location of the conduction system and the tip of the lead was observed under a light microscope. After iodine staining of the specimen, the His-purkinje conduction system was observed with the naked eye in a net-like distribution, and the lead tip was screwed deeply and fixed in the left bundle branch area of the left ventricular subendocardium in the ventricular septum. Masson and Goldner trichrome staining showed that left bundle branch pacing lead directly passed through the left bundle branch when there was left bundle branch potential with left bundle branch current of injury, while it was not directly contact the left bundle branch when there was left bundle branch potential without left bundle branch current of injury. The left bundle branch current of injury observed on intracardiac electrocardiogram during His-purkinje conduction system pacing suggests that the pacing lead directly contacted the conduction bundle or its branches, therefore, the captured threshold was relatively low. Left bundle branch current of injury can be used as an important anatomic and electrophysiological evidence of left bundle branch capture.
探讨左束支起搏导线尖端与左束支解剖位置的关系以及左束支损伤电流的机制。阐明术中左束支损伤电流的临床价值。将起搏导线植入两只活体猪的心脏。术中电生理研究证实，在低输出时可夺获左束支或仅深层左心室间隔。术后立即用碘对猪心脏大体标本进行染色，观察希氏-浦肯野传导系统在左心室心内膜的大体分布及其与导线的关系。随后，用福尔马林溶液固定猪心脏，在标记位置后取出起搏导线。然后将猪心脏切片，进行Masson染色和戈德纳三色染色，在光学显微镜下观察传导系统的解剖位置与导线尖端的关系。标本经碘染色后，肉眼观察希氏-浦肯野传导系统呈网状分布，导线尖端深深旋入并固定在室间隔左心室心内膜下的左束支区域。Masson染色和戈德纳三色染色显示，存在左束支损伤电流的左束支电位时，左束支起搏导线直接穿过左束支，而存在无左束支损伤电流的左束支电位时，导线未直接接触左束支。希氏-浦肯野传导系统起搏时心内心电图观察到的左束支损伤电流提示起搏导线直接接触传导束或其分支，因此，夺获阈值相对较低。左束支损伤电流可作为左束支夺获的重要解剖学和电生理学证据。
