Allograft Dysfunction in Heart Transplant

Adult heart-transplant patients, excluding those with a GFR less than 30 mL/min/1.73m2, contraindications to MRI and allergies to either regadenoson or gadolinium contrast, will be enrolled over 60 months. Patients will be recruited from UCSD. The investigators will specifically enroll all eligible heart-transplant patients. Brief protocol: Cardiac MRI is performed. Cine images in standard views are obtained. T1 and T2 mapping sequences are performed on short axis images pre- and post-gadolinium contrast. For stress imaging, intravenous regadenoson is given as a 0.4 mg bolus followed by a 5 mL saline flush. After 30 seconds, short-axis images are acquired for 30 consecutive heartbeats with administration of gadolinium. Rest imaging is performed 30 minutes after stress imaging. Lastly, late gadolinium enhancement images are obtained in standard views. Images are analyzed offline by a blinded independent reader. Patients will be followed for at least 1 year after enrollment for MACE. Peripheral blood and endomyocardial biopsies will also be collected, timing as per usual clinical care as well as for-cause, for single cell RNAseq analyses.