Computer simulation of the beating heart, with particular emphasis on the dynamics of the heart valves, is the fluid-structure interaction problem for which the immersed boundary method was originally developed. The mechanical function of the heart is coordinated and controlled, however, by an electrical system that is intrinsic to the heart itself. It turns out that the immersed boundary method can also be used for the computer simulation of cardiac electrical activity, thus providing a unified methodology for cardiac dynamics. Results will be shown as computer animations of the beating heart.