Prevalence and One-year Outcome of Carotid Sinus Hypersensitivity in Unexplained Syncope: A Prospective Cohort Study from South India

Background: Carotid sinus syndrome accounts for one third of patients who presents with unexplained syncope. Prevalence of carotid sinus hypersensitivity (CSH) in Indians has not been studied till now. Objectives: To assess the prevalence and associations of CSH in symptomatic patients above 50 years and to study its prognostic significance pertaining to sudden cardiac death, syncope, recurrent pre syncope and falls on 1 year follow up. Methods: Patients above 50 years who presented with unexplained syncope, recurrent syncope or falls were considered cases and those without these symptoms were considered as controls. All the patients underwent carotid sinus massage and their responses noted. All symptomatic patients were followed up and observed for events like sudden cardiac death, syncope, recurrent pre syncope and falls during 1 year follow up. Patients with recurrent syncope and predominant cardioinhibitory syncope were advised permanent pacemaker implantation. Results: A total of 252 patients were screened, 130 patients constituted cases and 49 patients constituted controls. CSH was demonstrable in 32% (n = 42) of cases as compared to 8% (n = 4) in controls (p