A rare case of an unexpected trigger of paroxysmal atrial fibrillation in the right atrial appendage diverticulum

Introduction: We describe a rare case of an adolescent girl with paroxysmal atrial fibrillation originating from the right atrial appendage diverticulum and successfully converted to sinus rhythm after surgical intervention. Methods: A 19-year-old girl was referred to the hospital for a catheter ablation of paroxysmal atrial fibrillation. Conventional ablation strategies are ineffective. Activation mapping showed the root of the free wall atrial appendage was first excited and catheter modeling (3D Carto map) shows a sac-like structure. Results: We did selective angiography and further Computed tomography angiography (CTA) and Transesophageal ultrasonography (TTE) which showed diverticulum originating from the right atrial appendage. Hence the patient was referred to cardiac surgery and had no recurrent atrial fibrillation at three months postoperative follow up. Conclusions: Right atrial appendage diverticula is an extremely rare malformation that can coexist with atrial tachyarrhythmia. Surgical ligation or excision of the abnormal structure with local ablation can achieve excellent results.