Complete heart block as a herald sign for cardiac lymphoma.

A previously well 48-year-old man presented with presyncope and was found to be in complete heart block. Blood tests, echocardiography and coronary angiography were reported as normal, and a dual chamber permanent pacemaker was inserted. Six months later he re-presented with breathlessness. His chest X-ray showed cardiomegaly and echocardiography revealed a 4.4 cm pericardial effusion. A CT thorax revealed a mass originating from the intra-atrial septum, extending into the right atrium and ventricle. There were multiple pulmonary lesions suspected to be metastases. Histology demonstrated high-grade B-cell lymphoma. He was treated with eight cycles of R-CHOP chemotherapy and showed good radiological and clinical improvement. Post-treatment echocardiography found severe left ventricular dysfunction with an ejection fraction of <20%. Heart failure medical therapy was optimised and the pacemaker was upgraded to a resynchronisation device. A repeat scan 6 months post device upgrade showed an improvement in ejection fraction to 45%-50%. © BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.