The purpose of this research is to detect episodes of rejection versus non-rejection after cardiac transplant and the diagnostic accuracy of an Artificial Intelligence (AI) algorithm using the data from an ECG (electrocardiogram) and Cardiac Ultrasound (Echocardiogram and/or point of care ultrasound).

Inclusion Criteria:

• Patients undergoing post-cardiac transplant endomyocardial biopsy, and the ability to provide informed consent and a consent for the study.

Exclusion Criteria:

• Refusal of study participation

Post-cardiac transplantation subjects, presenting to the cardiac catheterization laboratories at Mayo Clinic in Rochester, MN for routine surveillance biopsies or for diagnostic biopsies in the setting of clinical concern including rejection and graft dysfunction will be enrolled.