Carotid sinus syndrome: an overlooked cause of syncope.

Carotid sinus syncope was diagnosed during a 2-year period in 21 men and 5 women, aged 51 to 80 years, who had experienced 1 to 30 syncopal episodes during periods of time which varied from 1 day to 6 years. In 19 of these patients there was evidence of organic heart disease. Carotid sinus hypersensitivity of the cardioinhibitory type was present in 14 patients, the vasodepressor type in 1 patient, and a mixed type in 7 patients. In four patients with the cardioinhibitory response, the possibility of the vasodepressor response was not excluded. A pacemaker was placed in 17 patients, deferred in 4 patients and refused by 5 patients. Follow-up of patients with pacemakers over 9.5 +/- 7.0 (SD) months revealed recurrence of symptoms in two patients due to a previously unrecognized vasodepressor response. Follow-up of the patients without pacemakers was brief (4.6 +/- 3.7 months), and they remained asymptomatic, except for one patient with recurring vertigo.