Hiraoka M, Sano T
Am J Physiol. 1976 Aug;231(2):319-25. doi: 10.1152/ajplegacy.1976.231.2.319.
The role of the sinoatrial ring bundle (SARB) in internodal conduction was examined by the microelectrode technique in excised rabbit hearts. The spread of the sinus impluse to the surrounding tissues was shown to proceed anteriorly toward the right branch of the crista terminalis significantly faster than toward the other direction. Thus the right SARB and the right branch of the crista terminalis close to the sinus node were the earliest areas excited by the sinus impulse in the areas surrounding the sinus node. It was further shown that the activation sequence does not initiate from the right SARB to the right branch of the crista terminalis via the junction of these two structures. Cutting the SARB did not produce any delay in conduction from the sinus node to the atrioventricular (AV) node. The conduction velocity measured at the endocardial surface by two microelectrodes has proved that conduction in the crista terminalis was significantly faster than in the SARB. The upstroke of the action potential from the crista terminalis was also steeper than that from the SARB. These results suggest that the SARB is not the main route for impulse propagation from the sinus node to the AV node; the fastest internodal conduction therefore takes place with wide wave fronts, along the crista terminalis.
采用微电极技术，在离体兔心脏中研究了窦房环束（SARB）在结间传导中的作用。结果表明，窦房结冲动向周围组织的扩布，其向前朝向界嵴右支的速度明显快于向其他方向的速度。因此，右SARB和靠近窦房结的界嵴右支是窦房结周围区域中最早被窦房结冲动兴奋的部位。进一步研究表明，兴奋序列并非从右SARB经这两个结构的连接处传至界嵴右支。切断SARB并未导致从窦房结到房室（AV）结的传导出现任何延迟。用两个微电极在心内膜表面测量的传导速度证明，界嵴的传导速度明显快于SARB。界嵴动作电位的上升支也比SARB的更陡。这些结果提示，SARB并非窦房结至房室结冲动传导的主要途径；因此，最快的结间传导是以宽波阵面沿界嵴进行的。
