Clinical context and outcome of carotid sinus syndrome diagnosed by means of the 'method of symptoms'

Aims: The prevalence and outcome of carotid sinus syndrome (CSS) reported in the literature vary owing to differences in indications and methods of carotid sinus massage (CSM).

Methods and results: We performed CSM on all patients aged 40 years and above with unexplained syncope after the initial evaluation. Carotid sinus massage was performed in the supine and standing positions on both sides for 10 s during continuous electrocardiogram and blood pressure monitoring; CSS was diagnosed in the event of an abnormal response to CSM in association with reproduction of spontaneous symptoms ('method of symptoms'). From July 2005 to July 2012, CSS was found in 164 (8.8%) of 1855 patients (mean age 77 ± 9 years, 73% males): 81% had an asystolic reflex (mean pause 7.6 ± 2.2 s) and 19% a vasodepressor reflex (mean lowest systolic blood pressure 65 ± 15 mmHg). Potential multifactorial causes of syncope (orthostatic hypotension, bundle branch block, bradycardia, tachyarrhythmias) were found in 74% of patients. One hundred forty-one patients received the proper care [advice on lifestyle measures in all, discontinuation (#40) or reduction (#17) of antihypertensive drugs, pacemaker implantation (#57)] and were followed up for 39 ± 25 months. Syncope recurred in 23 patients; the actuarial syncopal recurrence rate was 7% at 1 year and 26% at 5 years. Total syncopal episodes decreased from 91 per year during the 2 years before evaluation to 21 episodes per year during follow-up (P = 0.001). On Cox proportional-hazards regression, a mixed or vasodepressor response to tilt testing was the only independent predictor of syncopal recurrence (hazard ratio = 1.8; P = 0.01).

Conclusion: Carotid sinus massage by means of the 'method of symptoms' indentifies a clinical syndrome with definite features and outcome. A treatment strategy involving lifestyle measures, reduction of antihypertensive drugs and cardiac pacing when appropriate is effective in reducing the syncopal recurrence rate.