This study will include all adult (18 years or older) patients who received a heart transplantation at MUSC. This study will conduct a chart review of all adult heart transplant participants to understand how different variables including, donor and recipient comorbidities, donor and recipient medical history, donor and recipient social determinants of health, recipient length of time on transplant waitlist, donor cause of death (morbidity), donor conditions when harvested, recipient presence of mechanical circulatory support (MCS) (temporary or permanent), recipient reason for transplant, recipient use of inotropes and/or vasopressors, recipient pre-transplant lab values, recipient pre-transplant ECHO, recipient pre-transplant right heart catheterization (RHC), donor lab and test values, other donor and recipient imaging studies, recipient surgical time and patient stay data, donor-recipient prediction heart mass (PHM) ratio, recipient medications, donor medications, post-transplant follow-up data, as well as other donor and/or recipient variables, will affect heart transplant outcomes.

There are two classes of drugs for preventing blood clots in patients with atrial fibrillation (AF), an irregular heartbeat, after cardiac surgery: antiplatelet drugs (like aspirin) and anticoagulants (blood thinners). This study aims to determine whether the addition of blood thinners to antiplatelet drugs will improve treatment outcomes in patients who develop AF after coronary artery bypass grafting (CABG) surgery.

In this study, you will be randomized (assigned to a group by chance--like flipping a coin) into one of 2 study groups; the assignment to receive the antiplatelet drug alone or the antiplatelet drug plus a blood thinner.

Before discharge from the hospital, you will undergo an electrocardiogram (ECG), which examines the electrical activity of your heart. At 1 and 2 months after randomization, you will receive a phone call from the study staff. At 3 months after randomization, you will return to the institution where you received your surgery for an in-person visit. At 6 months, you will receive a phone call from the study staff. Your total participation will be about 6 months.