The Left Atrial Appendage: Anatomy, Electrophysiology, and Clinical Implications for Atrial Fibrillation and Stroke

Purpose of Review The left atrial appendage (LAA) is nowadays recognized as both an arrhythmogenic substrate and the dominant source of thromboembolism in atrial fibrillation (AF). In this review we tried to summarize recent data on the anatomy, physiology, and imaging of the LAA, and examine how these findings help guide rhythm-control and stroke-prevention strategies. Recent Findings High-resolution mapping confirms the LAA as a non–pulmonary-vein trigger source in persistent and post-ablation AF, supporting LAA electrical isolation in selected patients, though isolation may induce mechanical standstill and mandate continued thromboprophylaxis. The 2024 ESC guidelines reframed stroke-risk assessment around the sex-neutral CHA₂DS₂-VA score within the AF-CARE pathway. An important recent study was the OPTION trial, which showed that LAA closure after AF ablation was as effective as oral anticoagulation for preventing death, stroke, or systemic embolism and was associated with less non–procedure-related bleeding. These findings support the use of LAA closure in selected patients after ablation. New imaging and emerging computational tools may also improve patient selection and help guide device sizing. Summary A comprehensive assessment of the anatomy, function, and electrical activity of the LAA can help adapt AF treatment to each patient.