Yanni Joseph, Boyett Mark R, Anderson Robert H, Dobrzynski Halina
Cardiovascular Research Group, Faculty of Medical and Human Sciences, University of Manchester, United Kingdom.
Heart Rhythm. 2009 May;6(5):672-80. doi: 10.1016/j.hrthm.2009.01.021. Epub 2009 Jan 21.
The so-called specialized tissues within the heart are the sinus node, the atrioventricular conduction system, and the Purkinje network. Further structures with the characteristics of specialized tissue are also found within the atrioventricular junction, although they are less well described.
The purpose of this study was to demonstrate the location and extent of these atrioventricular ring specialized tissues, showing their relationship with the normal atrioventricular conduction system.
We identified the tissues using histology combined with immunohistochemical labeling with connexin43 (Cx43), the major gap junction in heart, and HCN4, the major isoform of the funny channel.
We observed rings of specialized tissue mainly in hearts from rats, mice, and guinea pigs, negative for Cx43 but positive for HCN4. Each ring takes its origin from an inferior extension of the atrioventricular node. The rightward ring runs around the vestibule of the tricuspid valve, whereas the leftward ring encircles the mitral valve. On returning toward the atrial septum, the tricuspid ring crosses over the penetrating part of the atrioventricular conduction system, reuniting with the mitral ring to form a superiorly located retroaortic node. The atrioventricular conduction system itself continues beyond the origin of the right and left bundle branches, forming an aortic ring that ascends toward the retroaortic node but fails to make contact because of the intervening area of aortic-to-mitral valvar fibrous continuity.
Rings of conduction tissue take their origin from inferior extensions of the atrioventricular node, passing rightward and leftward to encircle the orifices of the tricuspid and mitral valves and reuniting to form an extensive retroaortic node. Thus, a ring with morphologic features justifying a definition of specialized conduction tissue surrounds the atrioventricular junctions, although its function has yet to be established.
心脏内所谓的特殊组织是窦房结、房室传导系统和浦肯野网络。尽管对其描述较少，但在房室交界处也发现了具有特殊组织特征的其他结构。
本研究的目的是展示这些房室环特殊组织的位置和范围，显示它们与正常房室传导系统的关系。
我们使用组织学结合连接蛋白43（Cx43，心脏中的主要缝隙连接）和HCN4（起搏电流通道的主要亚型）的免疫组化标记来识别组织。
我们主要在大鼠、小鼠和豚鼠的心脏中观察到特殊组织环，其对Cx43呈阴性，但对HCN4呈阳性。每个环起源于房室结的下延部分。向右的环围绕三尖瓣前庭，而向左的环环绕二尖瓣。在返回房间隔时，三尖瓣环穿过房室传导系统的穿入部分，与二尖瓣环重新汇合，形成位于上方的主动脉后结。房室传导系统本身在左右束支起源之外继续延伸，形成一个主动脉环，该环向上朝向主动脉后结，但由于主动脉与二尖瓣瓣叶纤维连续性的中间区域而未能接触。
传导组织环起源于房室结的下延部分，向右和向左延伸以环绕三尖瓣和二尖瓣口，并重新汇合形成一个广泛的主动脉后结。因此，一个具有形态学特征足以定义特殊传导组织的环围绕着房室交界处，尽管其功能尚未确定。
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