The optimized instantaneous percent modulation (■) and optimized minute percent modulation (●) (medians ± SE) at TVs of 0, 250, 500, and 750 ml, computed across all animals (n = 10), for body surface (A), CS (B), LV (C), RV (D), and RV-CS leads (E). For every lead configuration, as the TV increases, the percent modulation also increases.