Consented heart transplant recipients provided 8-10 mL of whole blood, which was extracted from the right jugular vein, the same point of entry for the biopsy, and centrifuged at 1900 x g at room temperature for 10 minutes to fractionate the blood. The entire plasma layer was transferred into 2-3 2.0 mL Eppendorf tubes and centrifuged at maximum speed (13,000 RPM) for 16 minutes at 4oC. The resulting supernatant was then used to isolate cell free DNA using the semi-automated MagNA Pure 24 System (Roche).The extracted cell free DNA was then bisulfite coverted using the Epitect Bisulfite Kit (Qiagen). Libraries were prepared using the Illumina MiSeq library preparation kit. Libraries were then sequenced using the v3 MiSeq reagent kit v3 (150 cycles) to produce 2x75 bp paired-end reads