Carotid sinus hypersensitivity (CSH) is defined by pause ≥ 3 seconds (sinus or atrioventricular block) and/or systolic blood pressure drop ≥ 50mmHg during carotid sinus massage (CSM). The prevalence of CSH varies according to the method and population evaluated in up to 68% of elderly patients with syncope and 35% of asymptomatic individuals over 65 years of age. Therefore, the cause-effect relationship between carotid sinus hypersensitivity and syncope should always be questioned, and may only be a casual finding and not necessarily the carotid sinus syndrome (CSS), one of the causes of syncope seen mainly in elderly patients.

The clinical relevance of CSH obtained with CSM was questioned in a study recently published by Wu et al. The authors compared the response to CSM between 99 patients with syncope to clarify and 66 asymptomatic patients and found similar rates of CSH between the two groups, with cardioinhibitory response in 24.2 and 25.8% and vasodepressor response in 8.1 and 13.6%, in symptomatic and asymptomatic patients respectively (p = 0.466). Therefore, CSH may be a nonspecific response in the evaluation of syncope in these patients with dubious clinical significance, especially in the elderly population with multiple comorbidities, often with the possibility of varying etiologies.

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