均匀心肌组织中心室颤动机制的仿真研究

目的研究心肌中的局部传导阻滞现象,在细胞水平上解释颤动中螺旋波的形成和破裂为多重子螺旋波的机制,强调动作电位时程(APD)恢复特性对心室颤动的诱发和维系具有重要意义。方法从心肌细胞APD恢复特性和传导速度(CV)恢复特性出发,利用非线性动力学方法,基于一维均匀心肌组织模型,观察不同起搏频率下的APD现象。结果证明了单个心肌细胞的APD交替以及均匀心肌组织中的非同步交替现象,并在起搏位置的远端发现了局部传导阻滞。结论均匀心肌组织中,由于APD和CV恢复特性的相互作用,在高频率起搏时,足以产生局部传导阻滞,从而可能进一步诱发螺旋波及破裂成心室颤动。

Mechanism of ventricular fibrillation induction in simulated one-dimensional homogeneous cardiac tissue

Objective To study the local conduction block in homogeneous cardiac tissue, which may be used to explain how the spiral waves are initialized and then broken into multiple wavelets in the induction of ventricular fibrillation (VF). Methods Based on the action potential duration (APD) restitution property of cardiac cell and conduction velocity (CV) restitution property in cardiac tissue, the nonlinear dynamical analysis on one-dimensional homogeneous cardiac tissue was proceeded. The tissue was paced with different frequencies. Results The simulations here suggested that there were APD alternans in single cell and discordant alternans in cardiac tissue away from the activation point which was paced in low basic cycle length (BCL). With the more lowering of BCL, the discordant alternans developed further into local conduction block. Conclusions The interplay of the APD and CV is enough to induce local conduction block in spatially homogeneous cardiac tissue, which may induce the spiral wave and its breakup into multiple wavelets.