| Altered systemic hemodynamic and baroreflex response to angiotensin II in postural tachycardia syndrome. | |
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MedLine Citation:
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PMID: 22247480 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Postural tachycardia syndrome (POTS) is characterized by excessive orthostatic tachycardia and significant functional disability. We have previously found that patients with POTS have increases in plasma angiotensin II (Ang II) that are twice as high as healthy subjects despite normal blood pressures (BPs). In this study, we assess systemic and renal hemodynamic and functional responses to Ang II infusion in patients with POTS compared with healthy controls. METHODS AND RESULTS: Following a 3-day sodium-controlled diet, we infused Ang II (3 ng/kg per minute) for 1 hour in patients with POTS (n=15) and healthy controls (n=13) in the supine position. All study subjects were women with normal BP. Ages were similar for patients with POTS and controls (mean±SEM, 30±2 versus 26±1 years; P=0.11). We measured the changes from baseline mean arterial pressure, renal plasma flow, plasma renin activity, aldosterone, urine sodium, and baroreflex sensitivity in both groups. In response to Ang II infusion, patients with POTS had a blunted increase compared with controls in mean arterial pressure (10±1 versus 14±1 mm Hg, P=0.01) and diastolic BP (9±1 versus 13±1 mm Hg, P=0.01) but not systolic BP (13±2 versus 15±2 mm Hg, P=0.40). Renal plasma flow decreased similarly with Ang II infusion in patients with POTS versus controls (-166±20 versus -181±17 mL/min per 1.73 kg/m(2), P=0.58). Postinfusion, the decrease in plasma renin activity (-0.9±0.2 versus -0.6±0.2 ng/mL per hour, P=0.43) and the increase in aldosterone (17±1 versus 15±2 pg/mL, P=0.34) were similar in both groups. The decrease in urine sodium excretion was similar in patients with POTS and controls (-49±12 versus -60±16 mEq/g creatinine, P=0.55). The spontaneous baroreflex sensitivity at baseline was significantly lower in patients with POTS compared with controls (10.1±1.2 versus 16.8±1.5 ms/mm Hg, P=0.003), and it was further reduced with Ang II infusion. CONCLUSIONS: Patients with POTS have blunted vasopressor response to Ang II and impaired baroreflex function. This impaired vasoconstrictive response might be exaggerated with upright posture and may contribute to the subsequent orthostatic tachycardia that is the hallmark of this disorder. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00962949. |
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Authors:
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Hossam I Mustafa; Satish R Raj; André Diedrich; Bonnie K Black; Sachin Y Paranjape; William D Dupont; Gordon H Williams; Italo Biaggioni; David Robertson |
Publication Detail:
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Type: Journal Article; Randomized Controlled Trial; Research Support, N.I.H., Extramural Date: 2012-01-13 |
Journal Detail:
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Title: Circulation. Arrhythmia and electrophysiology Volume: 5 ISSN: 1941-3084 ISO Abbreviation: Circ Arrhythm Electrophysiol Publication Date: 2012 Feb |
Date Detail:
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Created Date: 2012-02-15 Completed Date: 2012-04-17 Revised Date: 2012-05-24 |
Medline Journal Info:
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Nlm Unique ID: 101474365 Medline TA: Circ Arrhythm Electrophysiol Country: United States |
Other Details:
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Languages: eng Pagination: 173-80 Citation Subset: IM |
Affiliation:
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Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-2195, USA. |
| Data Bank Information | |
Bank Name/Acc. No.:
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ClinicalTrials.gov/NCT00962949 |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adolescent Adult Angiotensin II / administration & dosage, therapeutic use* Baroreflex / drug effects* Dose-Response Relationship, Drug Female Follow-Up Studies Hemodynamics / drug effects* Humans Infusions, Intravenous Middle Aged Postural Orthostatic Tachycardia Syndrome / drug therapy, physiopathology* Retrospective Studies Treatment Outcome Vasoconstrictor Agents / administration & dosage, therapeutic use Young Adult |
| Grant Support | |
ID/Acronym/Agency:
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K23 RR020783/RR/NCRR NIH HHS; K23 RR020783-05/RR/NCRR NIH HHS; P01 HL056693/HL/NHLBI NIH HHS; P01 HL056693-16/HL/NHLBI NIH HHS; R01 HL071784-08/HL/NHLBI NIH HHS; R01 HL102387-02/HL/NHLBI NIH HHS; R01HL071784/HL/NHLBI NIH HHS; R01HL102387/HL/NHLBI NIH HHS; U54 NS065736/NS/NINDS NIH HHS; U54 NS065736-03/NS/NINDS NIH HHS; UL1RR024975/RR/NCRR NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Vasoconstrictor Agents; 11128-99-7/Angiotensin II |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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