Complete Heart Block and Nonsustained Ventricular Tachycardia Secondary to Cardiac Metastases From Breast Cancer

Although breast cancer is known to metastasize to the heart, arrhythmias associated with this are unusual.

A 62-year-old woman with a past oncological history was admitted after an incidental finding of complete heart block. Ambulatory Holter monitoring also revealed episodes of nonsustained ventricular tachycardia. Subsequent imaging confirmed cardiac metastases. The patient was managed with permanent leadless pacemaker implantation and initiation of beta-blocker therapy.

Cardiac involvement from metastatic disease is well documented, including from breast cancer, but presentations with arrhythmias, including complete heart block and ventricular tachycardia, are particularly rare. To our knowledge, no previous cases of breast cancer presenting in this way have been reported.

When a patient with a known malignancy presents with new-onset cardiac symptoms, the possibility of cardiac metastases should be considered. Multimodality imaging and a multidisciplinary approach are crucial in diagnosing cardiac metastases.