Post-transplant atrial tachyarrhythmias: Epidemiology, mechanisms, outcomes, and management across solid organs.

Post-transplant atrial tachyarrhythmias - including atrial fibrillation (AF), atrial flutter, and organized atrial tachycardias - occur after solid-organ transplantation and follow distinct time- and organ-dependent patterns. Early arrhythmias are mainly postoperative, resulting from inflammatory and autonomic stress, hemodynamic and metabolic shifts, and atrial injury. Thoracic transplantation bears the highest burden: Early postoperative AF is frequent, while late arrhythmias typically present as macroreentrant tachycardias at anastomotic or incisional sites. These late arrhythmias can signal graft pathology or atrial remodeling. In heart transplantation, late atrial tachyarrhythmias depend on surgical technique and often coincide with rejection or cardiac allograft vasculopathy. In abdominal transplantation, AF is less common but remains relevant. In liver transplantation, AF links closely to advanced disease and perioperative instability, with poorer outcomes. Across organs, post-transplant AF leads to longer hospitalization and higher risks of thromboembolism, mortality, and graft loss, emphasizing its significance beyond a brief postoperative event. Management is complex and multidisciplinary, requiring careful evaluation for reversible causes, patient-specific rate-control or rhythm-control, and attention to interactions among antiarrhythmics, anticoagulants, and immunosuppressive agents. Rhythm control is increasingly mechanism-driven. Catheter ablation, at experienced centers, is effective for late organized tachyarrhythmias, achieving high acute and durable success in recent single-center series. Stroke prevention remains difficult due to changing bleeding risk, organ function, and limited relevant trial evidence. Anticoagulation requires ongoing reassessment. Left atrial appendage occlusion is an emerging alternative for patients ineligible for long-term anticoagulation. Evidence, mainly from registry data and small series, suggests potentially higher vascular complication rates. This review summarizes current knowledge, clarifies knowns and unknowns, and describes future goals, including standardized definitions, phenotyping, surveillance windows, transplant-specific risk stratification, and comparative studies of anticoagulation, ablation, and appendage-closure strategies to improve outcomes.