library_construction_protocol: Total cells were sorted from the heart of WT, Myh6-R404Q or Prkag2-p.R299Q point mutation mouse model. The single cells were obtained by the method of digesting by collagenase and grinding through a 70 μm cell strainer for scRNA-seq. Library construction was performed according to the manufacture's protocol(Single Cell 3′ library and Gel Bead Kit v.3).Briefly, GEMs (Gel Bead in Emulsion) were constructed for single cell separation according to the number of cells to be harvested. After GEMs were normally formed, GEMs were collected for reverse transcription in a PCR machine for labeling. The GEMs were oil-treated, and the amplified cDNA was purified by magnetic beads, and then subjected to cDNA amplification and quality inspection. The 3ʹ Gene Expression Library was constructed with the quality-qualified cDNA. After fragmentation,  adaptor ligation, sample index PCR, etc., the library is finally quantitatively examined.