Cardioinhibitory carotid sinus hypersensitivity. Intracardiac recordings and clinical assessment.

Cardioinhibitory carotid sinus hypersensitivity most frequently occurs in elderly men, predominantly during right carotid massage. Resting sinus bradycardia and aortic stenosis may be unusually prevalent in this subgroup of patients. Ventricular arrest occurs abruptly and may be preceded by brief prolongation of sinus cycle lengths and atrioventricular nodal conduction times. Gradual recovery of the sinoatrial rate follows resumption of sinus rhythm and is preceded by atrioventricular nodal recovery. His bundle electrocardiography is valuable in excluding other potential causes of syncope in patients with carotid sinus hypersensitivity. Despite a history of syncope, permanent pacing may not be indicated in the management of patients with carotid sinus hypersensitivity and otherwise normal electrophysiologic study.