The LVAD core collected at the time of LVAD implant was digested, PBMCs were isolated form peripheral blood of the same patient and "digested" similarly to the LVAD core. Cells were frozen in DMSO and media. Samples from two patients were collected. Eventually, cells were thawed, CD45+ CD19+ cells were FACS sorted and B cells from heart and blood were analyzed in the same 10X single cell sequencing reaction. Cells from heart and blood were marked with 2 different hashtag antibodies.