(A) Model with mixed distances between mitochondria and CaRUs. The distances were adjusted to 50, 200, and 50 nm. (B) Reponses of [Ca]mito (upper), NADH (middle), and Pi (lower) to alterations in pacing rate. Black line, control model (distance = 50 nm); gray line, large-distance model (distance = 200 nm); red line, mixed distance.