Initial orthostatic hypotension among patients with unexplained syncope: An overlooked diagnosis?

摘要

Background: Initial orthostatic hypotension (IOH) is a clinical syndrome of transient orthostatic hypotension that is defined as a drop in blood pressure of 40 mmHg systolic and/or 20 mmHg diastolic within 15 s after standing, accompanied by symptoms of cerebral hypoperfusion, but without sustained orthostatic hypotension (blood pressure decrease 20/10 mm Hg after 1-3 min of standing). As the etiology of syncope remains unknown in a large proportion of patients, we hypothesized that IOH is highly prevalent among patients with unexplained syncope.