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Auton Neurosci. 2014 Oct;185:107-11. doi: 10.1016/j.autneu.2014.06.003. Epub 2014 Jun 21.

Decreased orthostatic adrenergic reactivity in non-dipping postural tachycardia syndrome.

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Department of Neurology, Mayo Clinic, Rochester, MN, United States.
Department of Internal Medicine, Mayo Clinic, Rochester, MN, United States.
Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN, United States.
Department of Cardiology, Mayo Clinic, Scottsdale, AZ, United States.
Department of Neurology, Mayo Clinic, Rochester, MN, United States. Electronic address:


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±14.0bpm vs. 74.0±13.8bpm, P=0.532); or 5) supine plasma norepinephrine level (250.0±94.9pg/ml vs. 207.0±86.8pg/ml, P=0.08). However, dippers differed significantly from non-dippers in that they had significantly greater orthostatic heart rate increment (43±16bpm vs. 35±10bpm, P=0.007) and significantly greater orthostatic plasma norepinephrine increase (293±136.6pg/ml vs. 209±91.1pg/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.


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

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