TY - JOUR
T1 - Mechanisms of blood pressure alterations in response to the Valsalva maneuver in postural tachycardia syndrome
AU - Sandroni, Paola
AU - Novak, Vera
AU - Opfer-Gehrking, Tonette L.
AU - Huck, Christine A.
AU - Low, Phillip A.
PY - 2000
Y1 - 2000
N2 - The postural tachycardia syndrome (POTS) is characterized clinically by orthostatic lightheadedness and tachycardia. When these patients perform a Valsalva maneuver, there is an excessive blood pressure increment after cessation of the maneuver (phase IV) that is sometimes associated with headaches. It is not known whether excessive phase IV is due to excessive peripheral vascular tone (an α-adrenergic mechanism) of is a manifestation of increased β-adrenergic tone (hyperadrenergic state). The authors undertook a pharmacologic study evaluating the effect of intravenous phentolamine (α-adrenergic antagonist) and propranolol (β-adrenergic antagonist) on the different phases of the Valsalva maneuver in a group of patients with POTS and age-matched normal control subjects. Patients with POTS had mean phases, when compared with controls, that were characterized by more negative II_E (p = 0.07), smaller II_L (p = 0.04), and significantly larger phase IV (p = 0.001). The effect of phentolamine was qualitatively and quantitatively different in POTS when compared with controls. Ten mg phentolamine in controls resulted in a significant accentuation of phase II_E (p = 0.001), attenuation of phase II_L (p = 0.002), and increase of phase IV (57.6 vs 30.7 mm Hg; p = 0.025). These changes resembled those of patients with POTS at baseline. In patients with POTS, the phase II abnormalities, already present, were further accentuated (p <0.001), and phase IV became smaller (50.6 vs 73.8 mm Hg; p = 0.09). Propranolol had no significant effect on phases II_E and II_L, but significantly reduced phase IV in both controls (p <0.05) and in patients with POTS (p <0.001) and improved the headache symptoms, when present, during and after phase IV. The authors conclude that phase IV is mainly under β-adrenergic regulation and that the exaggerated phase IV in POTS is a result of a hyperadrenergic state.
AB - The postural tachycardia syndrome (POTS) is characterized clinically by orthostatic lightheadedness and tachycardia. When these patients perform a Valsalva maneuver, there is an excessive blood pressure increment after cessation of the maneuver (phase IV) that is sometimes associated with headaches. It is not known whether excessive phase IV is due to excessive peripheral vascular tone (an α-adrenergic mechanism) of is a manifestation of increased β-adrenergic tone (hyperadrenergic state). The authors undertook a pharmacologic study evaluating the effect of intravenous phentolamine (α-adrenergic antagonist) and propranolol (β-adrenergic antagonist) on the different phases of the Valsalva maneuver in a group of patients with POTS and age-matched normal control subjects. Patients with POTS had mean phases, when compared with controls, that were characterized by more negative II_E (p = 0.07), smaller II_L (p = 0.04), and significantly larger phase IV (p = 0.001). The effect of phentolamine was qualitatively and quantitatively different in POTS when compared with controls. Ten mg phentolamine in controls resulted in a significant accentuation of phase II_E (p = 0.001), attenuation of phase II_L (p = 0.002), and increase of phase IV (57.6 vs 30.7 mm Hg; p = 0.025). These changes resembled those of patients with POTS at baseline. In patients with POTS, the phase II abnormalities, already present, were further accentuated (p <0.001), and phase IV became smaller (50.6 vs 73.8 mm Hg; p = 0.09). Propranolol had no significant effect on phases II_E and II_L, but significantly reduced phase IV in both controls (p <0.05) and in patients with POTS (p <0.001) and improved the headache symptoms, when present, during and after phase IV. The authors conclude that phase IV is mainly under β-adrenergic regulation and that the exaggerated phase IV in POTS is a result of a hyperadrenergic state.
KW - POTS
KW - Phentolamine
KW - Propranolol
KW - Valsalva
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U2 - 10.1007/BF02291382
DO - 10.1007/BF02291382
M3 - Article
C2 - 10750636
AN - SCOPUS:0034463372
SN - 0959-9851
VL - 10
SP - 1
EP - 5
JO - Clinical Autonomic Research
JF - Clinical Autonomic Research
IS - 1
ER -