library_construction_protocol: Harvested hearts were placed in a Langendorff setup and perfused with a Type II Collagenase and Protease digestion buffer and stepped up with Calcium to 1 mM. Viable CMs were sorted using LP-FACS. The Union Biometrica COPAS Flow Platform was used to select CMs based on extinction, time of flight, and red fluorescence. SCRB-seq was used to construct the libraries.