Figure 2.

Effect of stochastic pacing on concordant alternans. (a) APD as a function of beat number for a mean BCL = 295 ms. Black and red graphs correspond to deterministic and stochastic (with σ = 1.5 ms) pacings, respectively. The bottom panel shows a short segment corresponding to the time interval marked by the green box. (b) Membrane voltage during deterministic (top) and stochastic (bottom) pacings for the last 10 beats from panel a. Significant alternans appeared during deterministic pacing and were significantly diminished with pacing stochasticity. (c) One case in which APD alternans during stochastic pacing exhibited amplitude similar to that observed during deterministic pacing. Panel organization as in panel a.