The hypotensive phenotype of autonomic syncope is characterized by hypotension as the predominant hemodynamic mechanism underlying loss of consciousness [1,2]. The term hypotensive phenotype encompasses both all forms of reflex syncopes (vasovagal, situational, carotid sinus, atypical and complex forms) and syncope due to orthostatic hypotension. The diagnostic criteria of hypotensive phenotype have been previously defined [1,3]. Hypotensive syncope is likely when one or more of the following criteria are met: induction of hypotensive syncope during tilt testing or carotid sinus massage, documentation of intermittent hypotensive episodes (orthostatic hypotension, post-prandial hypotension, hypotensive drops on 24-hour ambulatory blood pressure monitoring [ABPM]) or persistent hypotension.
