Malik M, Camm A J
Department of Cardiological Sciences, St. George's Hospital Medical School, London, United Kingdom.
Am J Physiol. 1989 Oct;257(4 Pt 2):H1263-74. doi: 10.1152/ajpheart.1989.257.4.H1263.
Wenckebach periodicity is characterized by progressive lengthening of conduction intervals and by progressive shortening of the intervals between conducted excitations. Although different hypotheses have been suggested to explain the mechanisms of Wenckebach periods, no serious proposition explaining both components of the phenomenon has yet been reported. A computer model simulating detailed mechanisms of excitation transmission and electrotonic interactions between neighboring cardiac cells has been employed to investigate the conduction properties of a one-dimensional cable composed of simulated cells. When introducing gradual prolongation of the recovery phase for the elements in the center of the cable and when incorporating physiologically realistic shapes of premature action potential curves into the simulation experiments, the model was able to reproduce all aspects of Wenckebach periodicity. Systematic evaluation with simulation experiments showed that a shorter duration of premature action potentials (i.e., of action potentials resulting from excitation of a cell before it has been fully repolarized) produced shortening of intervals between conducted excitations during a Wenckebach period.
文氏周期的特点是传导间期进行性延长以及下传激动之间的间期进行性缩短。尽管人们提出了不同的假说来解释文氏周期的机制，但尚未有能同时解释该现象两个组成部分的严谨观点被报道。一个模拟相邻心肌细胞间兴奋传导详细机制和电紧张相互作用的计算机模型，已被用于研究由模拟细胞组成的一维电缆的传导特性。当对电缆中部的元件引入恢复相的逐渐延长，并将生理现实的早搏动作电位曲线形状纳入模拟实验时，该模型能够重现文氏周期的所有方面。模拟实验的系统评估表明，较短的早搏动作电位持续时间（即细胞在完全复极之前被激动所产生的动作电位）会导致文氏周期期间下传激动之间的间期缩短。
