Case Report: Complete heart block as a manifestation of cardiac metastasis of oral cancer.

Metastatic tumors of the heart presenting with complete heart block (CHB) is an extremely uncommon case. There are no available guidelines in managing CHB in terminal cancer. Permanent pacemaker implantation in such cases is a challenge in terms of clinical utility and palliative care. We report a case of a 24-year-old man suffering from tongue cancer presenting with CHB. An intracardiac mass and moderate pericardial effusion were present, presumed as the metastatic tumor of tongue cancer. We implanted a temporary pacemaker for his symptomatic heart block and cardiogenic shock, and pericardiocentesis for his massive pericardial effusion. We decided that a permanent pacemaker would not be implanted based on the low survival rate and significant comorbidities. Multiple studies report a variable number of cardiac metastasis incidence ranging from 2.3% to 18.3%. It is rare for such malignancies to present with CHB. The decision to implant a permanent pacemaker is highly specific based on the risks and benefits of each patient. It needs to be tailored to the patient's functional status, comorbid diseases, prognosis, and response to conservative management.