Acute Heart Failure and Complete Heart Block in a Patient with Recurrent Diffuse Large B-Cell Lymphoma: A Case Report.

BACKGROUND Cardiac tumors are divided into 2 categories: primary, originating from the heart, and metastatic, which spread to the heart from a different location, with metastatic tumors representing the vast majority. Cardiac tumors, depending on the size and location, can predispose patients to arrhythmic or hemodynamic complications. We present a patient with a history of B-cell lymphoma (DLBCL) in remission for 3 years who developed acute onset congestive heart failure and complete heart block secondary to DLBCL invasion of the myocardium. CASE REPORT A 67-year-old female patient with a history of stage IV double-hit DLBCL in remission for 3 years presented with acute-onset heart failure. Nuclear medicine PET/CT revealed a massive poorly defined right lower anterior mediastinal mass extending into the entire cardiac base and right ventricular myocardium, with cardiophrenic and retroperitoneal adenopathy. Vital signs and laboratory test results were significant for a heart rate of 56 beats per min (bpm) and elevated brain natriuretic peptide. Electrocardiogram was significant for a complete heart block, maintained by a junctional escape rhythm. Biopsies of the mass revealed recurrence of DLBCL. The patient was treated with diuretics and later started on RICE chemotherapy. CONCLUSIONS Mediastinal DLBCL infiltrating the myocardium is aggressive and presents a treatment dilemma, as retreat of the mass from emergency chemotherapy can result in catastrophic complications. Our patient's condition, rarely described in literature, was severe blood flow obstruction and significant arrhythmia, both of which improved after only 1 cycle of chemotherapy and without need for permanent pacemaker.