Cardiac metastasis from a Pancoast tumour presenting with ST-segment elevation and 2:1 atrioventricular block: a case report.

Background: Cardiac metastases are significantly more common than primary cardiac tumours. Their clinical presentation varies depending on tumour size, location, and degree of myocardial or pericardial infiltration. Common manifestations include pericardial effusion, valvular dysfunction due to inflow or outflow obstruction, and conduction disturbances. 2:1 atrioventricular (AV) block secondary to cardiac metastases is rare. Case Summary: We report a case of a 69-year-old man with a Pancoast tumour who presented with hyperacute ST-segment elevation and 2:1 AV block. Transthoracic echocardiography (TTE) and positron emission tomography (PET) revealed intracardiac metastases. A permanent dual-chamber pacemaker was implanted for symptomatic 2:1 AV block. The patient died from advanced malignancy shortly after device implantation. Discussion: This case highlights 2:1 AV block as an uncommon manifestation of cardiac metastases. Multimodality imaging, particularly TTE, cardiac magnetic resonance imaging, and cardiac PET, plays a pivotal role in timely diagnosis. Permanent pacemaker implantation in such cases is a challenge in terms of clinical utility and palliative care. Decisions regarding permanent pacing should be shared between the patient and clinicians, incorporating balance between clinical indications, patient's comorbidities, prognosis, and preferences.