Overholt E D, Joyner R W, Veenstra R D, Rawling D, Wiedmann R
Am J Physiol. 1984 Oct;247(4 Pt 2):H584-95. doi: 10.1152/ajpheart.1984.247.4.H584.
Previous work has characterized the Purkinje-ventricular junction (PVJ) of papillary muscles as a region of low safety factor with some delay between P and V activation. We have previously shown that the P strand action potential activates a layer of P cells over most of the papillary muscle surface, but activation of the underlying V cells occurs only at specific junctional sites, generally near the base of the muscle. Our present results from both dog and rabbit left papillary muscles show that the junctional regions for propagation from the V layer up into the P layer include not only these specific P-to-V sites but also other sites located more toward the apex of the muscle. These results show that the papillary muscles have regions of potential unidirectional block, although the manifestation of unidirectional block at these sites requires the premature excitation of the ventricular layer.
先前的研究已将乳头肌的浦肯野-心室连接区（PVJ）描述为安全系数较低的区域，P波和V波激活之间存在一定延迟。我们之前已经表明，P波动作电位激活了乳头肌大部分表面的一层P细胞，但下层V细胞的激活仅发生在特定的连接部位，通常靠近肌肉基部。我们目前对犬和兔左乳头肌的研究结果表明，从V层向上传播到P层的连接区域不仅包括这些特定的P-to-V位点，还包括更多朝向肌肉顶端的其他位点。这些结果表明，乳头肌存在潜在的单向阻滞区域，尽管这些位点单向阻滞的表现需要心室层的过早兴奋。
