One major cause of death in the industrialized world is sudden cardiac death, which so far can be reliably treated only by applying strong electrical shocks. Developing improved methods, aiming at lowering shock intensity and associated side effects potentially has significant clinical implications. Thus, optogenetic stimulation using structured illumination has been introduced as a promising experimental tool to investigate mechanisms underlying multi-site pacing and to optimize potential low-energy approaches. Furthermore, an objective of this work is to strengthen the application of optogenetic tools for cardiac arrhythmia research, which in turn is expected to improve applicable technologies towards tissue-protective defibrillation.