Systems and methods for improved monitoring of excitation-contraction coupling and excitable cells are provided, which provide millisecond time resolution. The system is capable of continuously monitoring excitation-contraction coupling in a relatively high-throughput manner. The system includes a device for monitoring cell-substrate impedance, an impedance analyzer capable of impedance measurements at millisecond time resolution, electronic circuitry that can engage the device and selectively connect two or more electrode arrays of the device to the impedance analyzer and a software program that controls the electronic circuitry and records and analyzes data obtained from the impedance analyzer.