Carotid sinus syncope induced by malignant tumors in the neck. Emergence of vasodepressor manifestations following pacemaker therapy.

Three patients had carotid sinus syncope secondary to malignant neoplasms in the neck. Pacemaker therapy controlled the cardioinhibitory reflex with bradycardia, but the patients manifested varying episodes of hypotension due to a vasodepressor reflex that most likely resulted from persistent irritation of the carotid sinus by the tumor. These episodes seemed to be self-limiting. Surgical treatment in resistant cases is a possibility.