The history of diagnosing carotid sinus hypersensitivity: why are the current criteria too sensitive?

The carotid sinus syndrome and carotid sinus hypersensitivity (CSH) are closely related disorders. The first is characterized by syncope triggered by manipulation of the carotid sinus in daily life (e.g. shaving). According to the current European Society of Cardiology guidelines, CSH is diagnosed when carotid sinus massage elicits ≥3 s asystole, a fall in systolic blood pressure of ≥50 mmHg, or both, with symptoms. The question is, however, whether symptoms can be expected when these criteria are met. Although they are widely accepted, we will show that their basis is primarily in arbitrary clinical observations and that in the original publications the link between classification and clinical symptoms was often dubious. The current criteria for CSH are thus too sensitive, explaining the reported high prevalence of CSH in the general older population. The review will conclude with suggesting a stricter set of criteria for CSH that should be evaluated in future studies.