Department of Anatomy, Histology and Embryology, Faculty of Medicine, Semmelweis University, Budapest, Hungary; Heart and Vascular Center, Semmelweis University, Budapest, Hungary.
Department of Anatomy, Histology and Embryology, Faculty of Medicine, Semmelweis University, Budapest, Hungary.
Heart Rhythm. 2018 Feb;15(2):258-264. doi: 10.1016/j.hrthm.2017.09.044. Epub 2017 Oct 5.
Pulmonary vein (PV) myocardium is a known source of atrial fibrillation. A debated question is whether myocardial extensions into caval veins and coronary sinus (CS) have similar properties. No studies have documented specific pacemaker and/or conducting properties of human extracardiac myocardium.
The purpose of this study was to characterize the histology and immunohistochemical features of myocardial sleeves in the wall of cardiac veins.
Sections of 32 human hearts were investigated. Specimens of PVs, superior caval vein (SVC), CS, sinoatrial and atrioventricular nodes, and left ventricle were stained with Best's Carmine for selective staining of intracellular glycogen. Anti-connexin45 (Cx45)- and Cx43-specific antibodies were used to determine the conduction properties of extracardiac myocardium.
Myocardial sleeve was found in the wall of PVs of 15 of 16 hearts, 21 of 22 SVCs, and 8 of 8 CSs. Bundles of glycogen-positive cardiomyocytes exhibiting pale cytoplasm and peripheral myofibrils were observed in the venous sleeves. Strong Cx45 and weak Cx43 labeling was detected in the extracardiac myocardium. Similar staining pattern was observed for the pacemaker and conduction system, whereas ventricular myocardium exhibited prominent Cx43 and no Cx45 immunoreactivity.
Myocardial fibers of PVs, SVC, and CS exhibit morphology similar to that of Purkinje fibers and are enriched in glycogen. We provide data for the first time on prominent positive staining for Cx45 in the extracardiac myocardium, indicating its potential pacemaker and/or conducting nature.
肺静脉（PV）心肌是心房颤动的已知来源。一个有争议的问题是，腔静脉和冠状窦（CS）中的心肌延伸是否具有相似的特性。没有研究记录过人的心外膜心肌的特定起搏和/或传导特性。
本研究的目的是描述心外膜静脉壁心肌袖的组织学和免疫组织化学特征。
研究了 32 个人类心脏的切片。对 PVs、上腔静脉（SVC）、CS、窦房结和房室结以及左心室的标本进行了 Best's Carmine 染色，用于选择性染色细胞内糖原。使用抗连接蛋白 45（Cx45）和 Cx43 特异性抗体来确定心外膜心肌的传导特性。
在 16 个心脏中的 15 个、22 个 SVC 中的 21 个和 8 个 CS 中发现了心肌袖。在静脉袖中观察到具有淡染细胞质和周围肌纤维的糖原阳性心肌细胞束。在外膜心肌中检测到强 Cx45 和弱 Cx43 标记。起搏和传导系统观察到相似的染色模式，而心室心肌表现出明显的 Cx43 和无 Cx45 免疫反应性。
PVs、SVC 和 CS 的心肌纤维具有与蒲肯野纤维相似的形态，并且富含糖原。我们首次提供了心外膜心肌中 Cx45 明显阳性染色的数据，表明其潜在的起搏和/或传导特性。
