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Autonomic activity and biomarker behavior in different orthostatic intolerance syndromes


ᴀɴɴɪᴇ ɢꜱᴀᴍᴩᴇʟ

Rev Port Cardiol. 2015 Aug 26. pii: S0870-2551(15)00182-1. doi: 10.1016/j.repc.2015.03.009. [Epub ahead of print]
Autonomic activity and biomarker behavior in supine position and after passive postural stress in different orthostatic intolerance syndromes.
[Article in English, Portuguese]
Freitas J1, Azevedo E2, Santos R3, Maciel MJ4, Rocha-Gonçalves F3.
Author information
  • 1Serviço de Cardiologia, Centro Hospitalar São João, Porto, Portugal; Universidade do Porto, Faculdade de Medicina, Porto, Portugal. Electronic address: jppafreitas@gmail.com.
  • 2Serviço de Neurologia, Centro Hospitalar São João, Porto, Portugal.
  • 3Universidade do Porto, Faculdade de Medicina, Porto, Portugal.
  • 4Serviço de Cardiologia, Centro Hospitalar São João, Porto, Portugal.
Orthostatic intolerance (OI) syndromes are a confusing topic and determining a specific diagnosis to achieve optimal treatment can be troublesome. We sought to assess biomarker, hemodynamic and autonomic variables in OI patients (autonomic dysfunction [AD], postural orthostatic tachycardia syndrome [POTS] and neurally mediated syncope [NMS]) and healthy controls during supine and head-up tilt position in order to achieve a better diagnosis.

In response to head-up tilt, patients with AD presented a marked decrease in systolic blood pressure (SBP) (p=0.002), and a blunted increase in heart rate (HR) (p=0.04). Baroreceptor gain was almost absent in supine position and did not change in response to tilt. Patients with POTS had lower values of atrial natriuretic peptide (p=0.03) but similar neurohormonal biomarkers and hemodynamic and baroreceptor function in supine position compared to healthy subjects. However, in response to head-up tilting greater reductions in stroke volume (p=0.008) and baroreceptor gain (p=0.002) and greater rises in HR (p=0.001), total peripheral resistance (p=0.008), low frequency component of SBP variability (LF-SBP) (p=0.003) and plasma noradrenaline (p=0.03) were observed. Patients with NCS had similar biomarkers and autonomic indices to healthy subjects in supine position, but a larger decrease in baroreceptor gain (p=0.007) and a greater rise in LF-SBP (p=0.004) and plasma adrenaline (p=0.003) response to head-up tilting.

Although different OI syndromes share similar symptoms, including blurred vision, syncope and dizziness particularly during orthostatism, they differ markedly regarding biochemical, autonomic and hemodynamic parameters. Assessment of these differences may be helpful for better diagnosis and management.

Copyright © 2014 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Autonomic nervous system; Biomarcadores; Biomarkers; Intolerância ortostática; Orthostatic intolerance; Sistema nervoso autónomo; Teste de tilt; Tilt test



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