Determinants of Beat-to-Beat Variability of Repolarization Duration in the Canine Ventricular Myocyte: A Computational Analysis
Figure 5
Effect of cell-to-cell coupling on BVR.
A. APD (top panel) and STV (bottom panel) of two identical cells for various degrees of electrical coupling. Normal coupling (left vertical dashed line) and critical coupling for successful conduction in a one-dimensional strand of virtual myocytes (right vertical dashed line) are indicated. Both cells received external stimulation. B. Similar to panel A for two cells of which one is prolonged via current injection (−0.1 pA/pF). Cell-to-cell coupling causes a mild decrease in average STV (1.1 ms) that is more pronounced in the case of an asymmetrical cell pair (1.9 ms; inset). C. Effect of strand length on temporal (solid line) and spatial (dashed line) dispersion of repolarization in an asymmetrical one-dimensional strand. Half of the strand received additional current injection to prolong APD, similar to panel B. BVR decreased with increasing strand length, whereas spatial dispersion of repolarization increased for longer strands.