AtriClip device (AtriCure Inc.) is a surgical device approved for left atrial appendage (LAA) exclusion and available in 4-sizes: 35-, 40-, 45- and 50-mm. Device size is determined during surgery by measuring the LAA length at the base with forceps or using the associated Selection Guide. In contrast, transcatheter LAA closure devices are sized solely on preprocedural imaging without operator dependency. Appropriate sizing is crucial, as inappropriate sizing may lead to incomplete exclusion or d…