| Dissection of carotid sinus hypersensitivity: the timing of vagal and vasodepressor effects and the effect of body position. | |
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MedLine Citation:
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PMID: 21595633 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We assessed the timing of vagal and sympathetic factors that mediate hypotension during CSM (carotid sinus massage) in patients with carotid sinus hypersensitivity. We hypothesized that a fall in cardiac output would precede vasodepression, and that vasodepression would be exaggerated by head-up tilt. We performed pulse contour analyses on blood pressure recordings during CSM in syncope patients during supine rest and head-up tilt. In a subset we simultaneously recorded muscle sympathetic nerve activity supine. During supine rest, systolic blood pressure decreased from 150±7 to 107±7 mmHg (P<0.001) and heart rate from 64±2 to 39±3 beats/min (P<0.01). Cardiac output decreased with heart rate to nadir (66±6% of baseline), 3.1±0.4 s after onset of bradycardia. In contrast, total peripheral resistance reached nadir (77±3% of baseline) after 11±1 s. During head-up-tilt, systolic blood pressure fell from 149±10 to 90±11 mmHg and heart rate decreased from 73±4 to 60±7 beats/min. Compared with supine rest, cardiac output nadir was lower (60±8 compared with 83±4%, P<0.05), whereas total peripheral resistance nadir was similar (81±6 compared with 80±3%). The time to nadir from the onset of bradycardia did not differ from supine rest. At the onset of bradycardia there was an immediate withdrawal of muscle-sympathetic nerve activity while total peripheral resistance decay occurred much later (6-8 s). The haemodynamic changes following CSM have a distinct temporal pattern that is characterized by an initial fall in cardiac output (driven by heart rate), followed by a later fall in total peripheral resistance, even though sympathetic withdrawal is immediate. This pattern is independent of body position. |
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Authors:
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C T Paul Krediet; David L Jardine; Wouter Wieling |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Clinical science (London, England : 1979) Volume: 121 ISSN: 1470-8736 ISO Abbreviation: Clin. Sci. Publication Date: 2011 Nov |
Date Detail:
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Created Date: 2011-07-12 Completed Date: 2011-11-08 Revised Date: 2012-01-05 |
Medline Journal Info:
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Nlm Unique ID: 7905731 Medline TA: Clin Sci (Lond) Country: England |
Other Details:
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Languages: eng Pagination: 389-96 Citation Subset: IM |
Affiliation:
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Department of Medicine, Academic Medical Center at the University of Amsterdam, Amsterdam, The Netherlands. C.T.Krediet@amc.nl |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Aged Aged, 80 and over Blood Pressure Bradycardia / pathology Carotid Sinus / physiopathology* Female Heart Rate Hemodynamics Humans Hypersensitivity / physiopathology* Male Middle Aged Posture Retrospective Studies Syncope Vagus Nerve / pathology Vasodilation |
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