Carotid sinus syndrome. Report of five cases and review of the literature.

Five cases of carotid sinus syndrome are presented. The syndrome is defined by spontaneous attacks of dizziness and fainting which can be reproduced by graded pressure on one carotid sinus. Three forms of the clinical syndrome, cardioinhibitory, vasodepressor, and cerebral, are discussed. The hyperactive carotid sinsu reflex, in which there is ventricular asystole lasting at least 3 seconds or a decrease of more than 50 mm Hg in systolic and diastolic blood pressure, should be differentiated from this syndrome. Treatment modalities include reassurance, drugs, radiotherapy, cardiac pacemakers, and surgical approaches. Carotid sinus syndrome should be considered in the differential diagnosis of unexplained syncope, arteriovenous block, or inappropriate sinus bradycardia.