Reversible Atrial Fibrillation with Bradycardia Associated with Primary Cardiac B-Cell Lymphoma.

Primary cardiac lymphoma (PCL) only rarely occurs and it is defined as a lymphoma in which the bulk of the tumor is located within the heart and pericardium. A 53-year-old woman was referred due to dyspnea, and an electrocardiogram exhibited atrial fibrillation (AF). Echocardiography revealed no abnormal findings. Scintigraphy and a lymph node biopsy led to a diagnosis of PCL. After the start of chemotherapy, AF was converted to atrial tachycardia prior to sinus rhythm with a first-degree atrioventricular block, which was finally restored to a normal sinus rhythm. PCL is only rarely encountered, but it should be included in the differential diagnosis as a possible cause of AF, and such AF could be reversible if the patient can be treated in a timely manner.