摘要
"R-on-T"现象临床并不少见,但相对于心肌动作电位时程(APD)而言,相邻细胞间心肌电传导时间太短。该现象于同一心动周期时间跨度过大,但于非同一心动周期心脏异质性过大,故从脏器自身结构和功能而言,目前对该现象的描述和理解均不合理。而心室肌动作电位3相变化幅度大,高电位可成为激动源,超常期又易于激动,使该期集心肌兴奋的始动性、被动性、时间差异的微观性于一体,在心脏异质性增大的基础上,于特定神经内分泌条件下,相邻细胞间较小的APD差异为心律失常发生提供了可能,即易损期触发致再次激动。故虽从心电图分析而言,该现象既可描述为"R-on-T"现象,也可理解为"T-to-R"触发,但从其发生机制分析,应为"T-to-R",而非"R-on-T"。
The "R-on-T" phenomenon is not uncommon clinically, but the time of myocardial conductivity among adjacent cells is much shorter compared with the myocardial action potential duration(APD). In the same cardiac cycle, the time span is too long to the phenomenon; but in the different cardiac cycle, the difference of heterogeneity of the heart is too large. Therefore, the current description and understanding of this phenomenon is unreasonable based on the structure and function of the heart. In the phase 3 of myocardial APD exists supernormal period and voltage-difference changes, which can be excited and exciting. In this period, myocardical cells set the initiative and the passivity of excitement, the little time difference in an organic whole. On the basis of the increasing heterogeneity of the heart, arrhythmia can take place among the neighbouring cells with minor difference of APD and large voltage gradient under the condition of neuroendocrine disorder. Therefore, although the phenomenon can be described as "R-on-T" and "T-to-R" on electrocardiogram, it should be "T-to-R" instead of "R-on-T" in view of its mechanism.
引文
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