The overarching aim the Sasse group is to improve our mechanistic understanding of cardiac arrhythmia generation and termination and to develop novel optogenetic tools to fulfill this aim. The group showed the potential of optogenetics in the heart in vivo in 2020 and have since then contributed to moving the field of cardiac optogenetics forward with key publications reporting optogenetic manipulation of signaling cascades, analysis of fibroblast-cardiomyocyte coupling, gene transfer-enabled cardiac optogenetics and optogenetic defibrillation and cardioversion. With novel optogenetic tools and mechanistic insights on cardiac arrhythmia, the group also aims to develop drug screening for pro- and anti-arrhythmic effects as well as to propose novel therapeutic concepts for terminating cardiac arrhythmia.