Purpose of Review <p>Postoperative atrial fibrillation (POAF) and post pericardiotomy syndrome (PPS) are among the most common complications following cardiac surgery. This review explores their incidence, clinical features, risk factors, and shared inflammatory mechanisms. It also examines prevention and management strategies, with a focus on the relationship between PPS and POAF and remaining gaps in understanding.</p> Recent Findings <p>Pericardial inflammation and innate immune activation are central to the development of both POAF and PPS. Surgical trauma initiates cascades involving cytokines, oxidative stress, and atrial remodeling. PPS has been associated with a higher risk of atrial fibrillation in the early postoperative period. Although current prediction models do not provide optimal discrimination, several preventive strategies, including preoperative medications and surgical options, have been shown to reduce the risk of these complications. However, varying definitions and diagnostic criteria limit comparability across studies, and long-term data are scarce.</p> Summary <p>POAF and PPS are associated with significant morbidity, including longer hospital stays, readmissions, and cardiovascular complications. Identifying high-risk patients is essential to guide early interventions. The overlap in pathophysiology suggests PPS may trigger POAF, but causality remains unconfirmed. Future research should focus on clarifying their relationship, assessing the durability of preventive strategies, and establishing standardized diagnostic criteria to reduce heterogeneity and improve clinical decision-making.</p>