P319 Differences in adrenergic components of baroreflex response to valsalva maneuver in patients with postural tachycardia syndrome and healthy subjects

Autor: Luka Crnošija, Ivan Adamec, Dunja Pucic, Bojana Nevajdic, Mario Habek, Tereza Gabelić, Magdalena Krbot Skorić, Tomislav Mutak
Rok vydání: 2017
Předmět:
Zdroj: Clinical Neurophysiology. 128:e281
ISSN: 1388-2457
Popis: Objectives To evaluate differences in recently developed, non-standard adrenergic baroreflex sensitivity (BRS) indices between patients with postural tachycardia syndrome (PoTS) and healthy controls (HC). Methods Criteria for diagnosing PoTS were increment of heart rate (HR) ⩾ 30 bpm or raise of HR to ⩾ 120 bpm in the absence of orthostatic hypotension, and a history of orthostatic intolerance symptoms lasting at least 3 months. PoTS patients were further divided into hyperadrenergic (H) and non-hyperadrenergic (NH) group according to standing serum NA ⩾ 3.5 nmol/L cut-off criteria. Eighteen PoTS patients and 19 HC performed tilt-up test and Valsalva maneuver. Alternative adrenergic component of BRS (BRSa1), and alpha- ( α -BRSa) and beta-adrenergic ( β -BRSa) components of adrenergic BRS were calculated and compared between the groups. Results PoTS group had significantly higher α -BRSa compared to HC (6.97 ± 2.39 vs. 5.13 ± 2.14, p = 0.02). No differences between PoTS patients and HC were found for BRSa1 (34.29 ± 21.79 vs. 32.41 ± 28.52, p = 0.823), and β -BRSa (1.43 ± 0.69 vs. 1.54 ± 1.19, p = 0.714). When comparing NH PoTS (N = 13), and H PoTS patients (N = 5) no significant differences were found in any of studied indices, although NH patients had slightly higher BRSa1 index than H patients (39.22 ± 23.06 vs. 21.46 ± 11.73, p = 0.055). Discussion High percentage of PoTSis caused by distal peripheral sympathetic dysfunction resulting in inadequate vasoconstriction in lower extremities. Higher α -BRSa found in PoTS patients may reflect an exaggerated vasoconstrictive response attempt following hemodynamic stress. Conclusion Healthy subjects and PoTS patients exhibit different alpha-adrenergic response to Valsalva maneuver. Significance Adrenergic indices may be a useful tool in studying pathophysiological differences in autonomic dysfunctions.
Databáze: OpenAIRE