Hemodynamic patterns of common forms of transient loss of consciousness

The three panels show heart rate (HR) and blood pressure (BP) for vasovagal syncope (left, VVS), initial orthostatic hypotension (middle, iOH), and psychogenic pseudosyncope (right, PPS). Orange bars represent the duration of apparent loss of consciousness (LOC). The upward arrows indicate head-up tilt for vasovagal syncope and active standing for initial orthostatic hypotension. Downward arrows indicate tilt down for vasovagal syncope and falling for initial orthostatic hypotension. The vertical scales for heart rate and blood pressure are the same for the vasovagal syncope, initial orthostatic hypotension, and psychogenic pseudosyncope panels, but the time scale differs. Loss of consciousness in vasovagal syncope is accompanied by low heart rate and low blood pressure. In initial orthostatic hypotension, it is accompanied by low blood pressure and normal or high heart rate. In psychogenic pseudosyncope, apparent loss of consciousness is accompanied by normal to high heart rate and blood pressure. The blood pressure nadir of vasovagal syncope usually occurs many minutes after assuming the upright position, whereas this is a matter of seconds in initial orthostatic hypotension. (Source: Stewart JM, van Dijk JG, Balaji S, Sutton R. A framework to simplify paediatric syncope diagnosis. Eur J Pediatr 2023;182[11]:4771-80. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)