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Postural tachycardia syndrome: time frequency mappingOrthostatic tachycardia is common but its specificity remains uncertain. Our preliminary work suggested that using autonomic function testing in conjunction with time-frequency mapping (TFM), it might be possible to characterize a subset of the postural tachycardia syndrome (POTS), that is due to a restricted autonomic neuropathy. We describe 20 patients (17 women and 3 men, aged 14-43 years) with florid POTS and 20 controls (14 women and 6 men, aged 20-41 years). Autonomic failure was quantified by its distribution (cardiovagal, adrenergic and sudomotor) and severity, a symptom profile was generated, and spectral indices, based on modified Wigner distribution during rest and head-up tilt (80 degrees) were evaluated. During tilt-up POTS patients differed from controls by an excessive heart rate (> 130 bpm) (P < 0.001), and higher diastolic pressure (P < 0.01). During rest, cardiovagal oscillations (at respiratory frequencies [RF]) and slow rhythms at nonrespiratory frequencies (NONRF) (from 0.01 to 0.07 Hz) in R-R intervals (RRI) (P < 0.01) were reduced. Both RF and NONRF rhythms in RRI were further blunted with tilt-up (P < 0.001). Slow adrenergic vasomotor rhythms in blood pressure (BP) (approximately 0.07 Hz) surged with tilt-up and returned to normal levels afterwards. The index of sympatho-vagal balance (NONRF-Systolic BP (SBP)/RF-RRI) was dramatically increased in POTS (P < 0.001). Distal postganglionic sudomotor failure was observed, and impairment of the BP responses to the Valsalva maneuver (phase II) suggested peripheral adrenergic dysfunction. Persistent orthostatic dizziness, tiredness, gastrointestinal symptoms and palpitations were common in POTS patients. It is possible to identify a subset of POTS patients who have a length-dependent autonomic neuropathy, affecting the peripheral adrenergic and cardiovagal fibers, with relative preservation of cardiac adrenergic fibers.
Document ID
20040173081
Document Type
Reprint (Version printed in journal)
Authors
Novak, V. (Autonomic Disorders Research Center, Mayo Clinic Rochester, MN 55905, United States)
Novak, P.
Opfer-Gehrking, T. L.
Low, P. A.
Date Acquired
August 22, 2013
Publication Date
December 14, 1996
Publication Information
Publication: Journal of the autonomic nervous system
Volume: 61
Issue: 3
ISSN: 0165-1838
Subject Category
Aerospace Medicine
Funding Number(s)
CONTRACT_GRANT: PO1 NS32352
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 14-10
Clinical Trial
NASA Discipline Cardiopulmonary
Non-NASA Center
NASA Program Space Physiology and Countermeasures