Abstract
ObjectiveTo assess: (1) the frequency of an abnormally large fall in blood pressure (BP) upon standing from supine in patients with initial orthostatic hypotension (IOH); (2) the underlying hemodynamic mechanisms of this fall in BP upon standing from supine and from squatting.MethodsIn a retrospective study of 371 patients (≤30 years) visiting the syncope unit, the hemodynamic response to standing and squatting were studied in 26 patients who were diagnosed clinically with IOH, based on history taking only. In six patients changes in cardiac output (CO) and systemic vascular resistance (SVR) were determined, and the underlying hemodynamics were analyzed.Results15/26 (58 %) patients with IOH had an abnormally large initial fall in systolic BP (≥40 mmHg). There was a large scatter in CO and SVR response after arising from supine [ΔCO at BP nadir median −8 % (range −37, +27 %); ΔSVR at BP nadir median −31 % (range −46, +10 %)]. The hemodynamic response after squatting showed a more consistent pattern, with a fall in SVR in all six patients [ΔCO at BP nadir median +23 % (range −12, +31 %); ΔSVR at BP nadir median −42 %, (range −52, −35 %)].InterpretationThe clinical diagnosis of IOH is based on history taking, as an abnormally large fall in systolic BP can only be documented in 58 %. For IOH upon standing after supine rest, the hemodynamic mechanism can be either a large fall in CO or in SVR. For IOH upon arising from squatting a large fall in SVR is a consistent finding.
Highlights
Occasional light-headedness and seeing black spots upon standing from supine or arising from a squatting position are experienced in almost all, otherwise healthy, teenagersClin Auton Res (2016) 26:441–449 and young adults [1,2,3,4]
Interpretation The clinical diagnosis of initial orthostatic hypotension (IOH) is based on history taking, as an abnormally large fall in systolic blood pressure (BP) can only be documented in 58 %
Such orthostatic complaints immediately after standing up result from cerebral hypoperfusion due to transient fall in systemic blood pressure (BP) [1]. It has not been studied how often a large initial fall in BP can be documented in subjects referred with severe complaints of light-headedness and occasionally syncope during formal cardiovascular reflex testing, i.e., the test characteristics of the active standing test for the diagnosis of initial orthostatic hypotension (IOH) are unknown [1]
Summary
Occasional light-headedness and seeing black spots upon standing from supine or arising from a squatting position are experienced in almost all, otherwise healthy, teenagersClin Auton Res (2016) 26:441–449 and young adults [1,2,3,4]. In the general population frequent complaints of light-headedness or even (near) syncope are reported to occur in about 20 % of young subjects [1, 5, 6] Such orthostatic complaints immediately after standing up result from cerebral hypoperfusion due to transient fall in systemic blood pressure (BP) [1]. It has not been studied how often a large initial fall in BP can be documented in subjects referred with severe complaints of light-headedness and occasionally (near) syncope during formal cardiovascular reflex testing, i.e., the test characteristics of the active standing test for the diagnosis of initial orthostatic hypotension (IOH) are unknown [1]. The initial hemodynamic mechanisms underlying the BP fall upon standing and squatting are thought to be similar [1, 8], but this has never been studied
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