Persistent atrial fibrillation is a type of arrhythmia characterised by continuous irregular and rapid atrial electrical activity lasting longer than seven days or requiring intervention to restore normal rhythm. It matters clinically because it often necessitates more aggressive management than paroxysmal atrial fibrillation, including anticoagulation and rhythm control strategies to prevent complications. A key complication associated with persistent atrial fibrillation is an increased risk of thromboembolic stroke due to impaired atrial contraction and blood stasis.