Atrial Fibrillation in a Patient with a Giant Left Atrial Appendage

SUMMARY Among sustained arrhythmias, atrial fibrillation is one of the most common causes of pa- tient consultation. Its substrate comprises various mechanisms, including left atrial en- largement. In this report, we present the case of a 33 year-old woman with a history of palpitations, who was admitted to the emergency room due to atrial fibrillation with a rapid ventricular response. In the chest X-ray, the left border of the cardiac silhouette was de- formed. Subsequently, both the transesophageal echocardiogram and the magnetic reso- nance images showed a giant aneurysmal left atrial appendage, probably due to a pericar- dial defect. Treatment consisted of oral anticoagulation and atenolol, with a favorable pa- tient outcome.