Research Article

Clinical Autonomic Research

, Volume 20, Issue 2, pp 93-99

Distal sudomotor findings in postural tachycardia syndrome

  • Amanda Catherine PeltierAffiliated withAutonomic Dysfunction Center, Vanderbilt University School of MedicineDepartment of Neurology, Vanderbilt University School of Medicine Email author 
  • , Emily GarlandAffiliated withAutonomic Dysfunction Center, Vanderbilt University School of MedicineDepartment of Medicine, Vanderbilt University School of Medicine
  • , Satish R. RajAffiliated withAutonomic Dysfunction Center, Vanderbilt University School of MedicineDepartment of Medicine, Vanderbilt University School of MedicineDepartment of Pharmacology, Vanderbilt University School of Medicine
  • , Kyoko SatoAffiliated withAutonomic Dysfunction Center, Vanderbilt University School of MedicineDepartment of Clinical Pharmacology, Tokai University School of Medicine
  • , Bonnie BlackAffiliated withAutonomic Dysfunction Center, Vanderbilt University School of MedicineDepartment of Medicine, Vanderbilt University School of Medicine
  • , Yanna SongAffiliated withDepartment of Biostatistics, Vanderbilt University School of Medicine
  • , Lily WangAffiliated withDepartment of Biostatistics, Vanderbilt University School of Medicine
  • , Italo BiaggioniAffiliated withAutonomic Dysfunction Center, Vanderbilt University School of MedicineDepartment of Medicine, Vanderbilt University School of MedicineDepartment of Pharmacology, Vanderbilt University School of Medicine
  • , Andre DiedrichAffiliated withAutonomic Dysfunction Center, Vanderbilt University School of MedicineDepartment of Medicine, Vanderbilt University School of MedicineDepartment of Biomedical Engineering, Vanderbilt University School of Medicine
    • , David RobertsonAffiliated withAutonomic Dysfunction Center, Vanderbilt University School of MedicineDepartment of Neurology, Vanderbilt University School of MedicineDepartment of Medicine, Vanderbilt University School of MedicineDepartment of Pharmacology, Vanderbilt University School of Medicine

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Abstract

Objectives

Postural tachycardia syndrome (POTS) is a heterogeneous disorder characterized by excessive orthostatic tachycardia in the absence of orthostatic hypotension and by sympathetic nervous system activation. Postganglionic sudomotor deficits have been used to define a neurogenic postural tachycardia POTS subtype. Norepinephrine levels above 600 pg/ml have also been used to delineate patients with a hyperadrenergic state. This study aims to determine the relationship of sudomotor abnormalities to other aspects of dysautonomia in POTS.

Methods

Autonomic function was quantified in thirty women through tests of cardiovagal, adrenergic, and sudomotor function including quantitative sudomotor axon reflex testing (QSART) and spectral indices. Differences between patients with and without sudomotor dysfunction as defined by QSART and between patients with and without hyperadrenergic POTS were assessed with Mann–Whitney U test and Mantel–Haenszel Chi-Square test using a p value of 0.01 for significance. Spearman correlation coefficients were used to test raw sweat volume correlations with other variables.

Results

Of 30 women (ages 20–58), 17 patients (56%) had an abnormal QSART which was typically patchy and involved the lower extremity, while 13 patients had normal QSART results. Other autonomic tests, catecholamines or spectral indices did not correlate with QSART results. No differences in autonomic tests or spectral indices were observed between hyperadrenergic and non-hyperadrenergic POTS.

Interpretation

Our findings confirm that a large subset of POTS patients have sudomotor abnormalities which are typically patchy in distribution but do not correlate with other tests of autonomic function. Further studies are needed to determine the best method of endophenotyping patients with POTS.

Keywords

Orthostatic intolerance Tachycardia POTS Sudomotor Autonomic neuropathy Sweating