  For plane-wave and many-spiral states of the experimentally based Luo-Rudy 1
model of heart tissue in large (8 cm square) domains, we show that an explicit
space-time-adaptive time-integration algorithm can achieve an order of
magnitude reduction in computational effort and memory - but without a
reduction in accuracy - when compared to an algorithm using a uniform
space-time mesh at the finest resolution. Our results indicate that such an
explicit algorithm can be extended straightforwardly to simulate quantitatively
large-scale three-dimensional electrical dynamics over the whole human heart.
