Hidden problems in a case of atrial fibrillation.

Atrial fibrillation (AF) is the most common cardiac arrhythmia. However, the relation between congenital heart defects and the predisposition to AF is not fully understood. A 65-year-old male was admitted into the emergency department due to progressive dyspnea, orthopnea, palpitations, and edema. Transthoracic echocardiogram showed bi-atrial enlargement and dysplasia of the mitral leaflets with severe mitral regurgitation. Also, a membrane was noted in the LA, dividing the chamber into two parts, suggestive of cor triatriatum sinister. Coronary computed tomography angiography demonstrated a soft tissue septum in the left atrium. Multimodal evaluation is of vital importance for a complete approach, since, detected in time, it has an excellent prognosis.