Vasodepressor carotid sinus syncope associated with a neck mass.

We present the hemodynamic and autonomic features of recurrent purely vasodepressor syncope episodes in a patient with left-sided malignant cervical adenopathy involving the carotid sinus. Extreme hypotension lasting 10 to 30 minutes, without change in heart rate, occurred spontaneously and 20 seconds after head-turning. The baseline respiratory sinus arrhythmia, heart rate response to standing and Valsalva's maneuver, and cold-induced blood pressure elevation were normal, indicating normal baroreceptor function between episodes. The episodes abated after 1 week of bedrest but reappeared within 1 day of discharge from the hospital. Syncope no longer occurred after intracranial section of the left glossopharyngeal nerve and upper rootlets of the left vagus. Autonomic testing remained normal postoperatively. A review of the literature indicates that purely vasodepressor syncope has been more common with left carotid sinus lesions.