Decreased orthostatic adrenergic reactivity in non-dipping postural tachycardia syndrome

Juan J. Figueroa, Darlene M. Bott-Kitslaar, Joaquin A. Mercado, Jeffrey R. Basford, Paola Sandroni, Win Kuang Shen, David M. Sletten, Tonette L. Gehrking, Jade A. Gehrking, Phillip A. Low, Wolfgang Singer

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Whether non-dipping - the loss of the physiologic nocturnal drop in blood pressure - among patients with postural tachycardia syndrome (POTS) is secondary to autonomic neuropathy, a hyperadrenergic state, or other factors remains to be determined. In 51 patients with POTS (44 females), we retrospectively analyzed 24-hour ambulatory blood pressure recordings, laboratory indices of autonomic function, orthostatic norepinephrine response, 24-hour natriuresis and peak exercise oxygen consumption. Non-dipping (<. 10% day-night drop in systolic blood pressure) was found in 55% (n= 28). Dippers and non-dippers did not differ in: 1) baseline characteristics including demographic and clinical profile, sleep duration, daytime blood pressure, 24-hour natriuresis, and peak exercise oxygen consumption; 2) severity of laboratory autonomic deficits (sudomotor, cardiovagal and adrenergic); 3) frequency of autonomic neuropathy (7/23 vs. 8/28, P= 0.885); 4) supine resting heart rate (75.3 ± 14.0. bpm vs. 74.0 ± 13.8. bpm, P= 0.532); or 5) supine plasma norepinephrine level (250.0 ± 94.9. pg/ml vs. 207.0 ± 86.8. pg/ml, P= 0.08). However, dippers differed significantly from non-dippers in that they had significantly greater orthostatic heart rate increment (43 ± 16. bpm vs. 35 ± 10. bpm, P= 0.007) and significantly greater orthostatic plasma norepinephrine increase (293 ± 136.6. pg/ml vs. 209 ± 91.1. pg/ml, P= 0.028). Our data indicate that in patients with POTS, a non-dipping blood pressure profile is associated with a reduced orthostatic sympathetic reactivity not accounted for by autonomic neuropathy.

Original languageEnglish (US)
Pages (from-to)107-111
Number of pages5
JournalAutonomic Neuroscience: Basic and Clinical
Volume185
DOIs
StatePublished - Oct 1 2014

Keywords

  • Ambulatory blood pressure
  • Circadian blood pressure rhythm
  • Dipping
  • Orthostatic intolerance
  • Postural tachycardia syndrome

ASJC Scopus subject areas

  • Endocrine and Autonomic Systems
  • Clinical Neurology
  • Cellular and Molecular Neuroscience

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