The mouse heart has a high beating rate among mammalian species and characteritic E-C coupling properties to support rapid contraction and relaxation. The myocardium of the mouse has an action potential of extremely short duration and its contraction is highly dependent on sarcoplasmic reticulum function. There are difference from other species in autonomic regulation such as α-adrenoceptor mediated sustained negative inotropy and acetylcholine-induced positive inotropy. These must be considered when interpreting experimental results from transgenic mice. Nevertheless, the mouse heart would provide an interesting model for studies on myocardial excitation-contraction coupling mechanisms and their regulation.