[Development of cardiac tamponade and emergence of arrhythmia during chemotherapy for diffuse large B-cell lymphoma].

Cardiac involvement during lymphoma often causes complications, including arrhythmia. A 68-year-old male with cardiac tamponade was diagnosed with diffuse large B-cell lymphoma with cardiac involvement based on the presence of the tumor mass in the myocardium and lymphoma cells in the pericardial effusion. He developed atrial fibrillation, ventricular tachycardia, and atrial flutter after initiating chemotherapy. Following chemotherapy, sinus rhythm was restored without invasive treatment for arrhythmia, while the cardiac mass disappeared. No recurrent arrhythmias were observed. In lymphoma with cardiac involvement, unexpected arrhythmias can emerge after initiation of chemotherapy, which could potentially be related to accelerated cardiac remodeling owing to the rapid relief of cardiac damage. Follow-up using electrocardiogram is thus necessary during chemotherapy for cardiac lymphoma, despite the absence of arrhythmia at the time of diagnosis.