Post-orthotopic heart transplant atrial fibrillation: From mechanisms to management, with a retrospective analysis of anticoagulation

While orthotopic heart transplant (OHT) provides life-prolonging treatment to end-stage heart disease, there is a rising incidence of post-OHT atrial fibrillation (AF). Post-OHT AF poses a unique challenge to clinicians due to drug interactions between treatment and immunosuppression. Currently, there is a lack of comprehensive literature evaluating both mechanisms and treatment for post-OHT AF. This state-of-the-art contemporary review summarizes epidemiology, mechanisms, treatments, and anticoagulation strategies for post-OHT AF. Occurrence of post-OHT AF requires prompt investigation, especially for graft rejection. Unique post-OHT AF mechanisms are derived from surgical technique (donor sino-atrial and atrioventricular node dysfunction, suture line positioning, remnant recipient tissue, and catecholamine surges), arrhythmogenicity (graft rejection, accelerated coronary atherosclerosis), or intrinsic forces (cardiac remodeling). Metoprolol is the preferred rate control agent and provides a bridge to definitive management. Antiarrhythmics and cardioversion are viable temporizing strategies, but recurrence with medical management remains unknown. Definitive management with ablation reportedly has a low recurrence rate. Prior single-center studies have demonstrated that DOACs are safe and offer comparable thromboembolism risk reduction relative to other anticoagulants, although these analyses were limited by small sample sizes. To further evaluate this question, we conducted a propensity-matched analysis of 847 patients per anticoagulant group and found that DOAC use was associated with lower rates of intracranial hemorrhage, gastrointestinal bleeding, and epistaxis than warfarin. As OHT patients require attention to drug interactions with immunosuppressive agents, especially CYP3A4 and P-glycoprotein inhibitors, collaborative practice with clinical pharmacists is paramount. Future work should focus on treatment strategy, anticoagulation safety, and patient outcomes.