| Impact of changes in respiratory frequency and posture on power spectral analysis of heart rate and systolic blood pressure variability in normal subjects and patients with heart failure. | |
| | |
MedLine Citation:
|
PMID: 8774258 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
1. Autonomic dysfunction is a major feature of congestive cardiac failure and may have an important role in determining progression and prognosis. The low-frequency/high-frequency ratio derived from power spectral analysis of heart rate variability has been proposed as a non-invasive method to assess sympatho-vagal balance. However, the effects of different respiratory rates or posture are rarely accounted for, but may be relevant in patients with heart failure in whom clinical improvement is accompanied by a fall in respiratory rate and an increased proportion of the day in the upright position. 2. We have assessed the effect of controlled respiration at different rates (10, 15, 20 breaths/min or 0.17, 0.25 and 0.33 Hz), while supine and standing, on power spectral analysis of heart rate and blood pressure variability in 11 patients with heart failure and 10 normal subjects. 3. Heart rate variance and low-frequency power (normalized units) were reduced in patients with heart failure (absent in six). During controlled breathing while supine, the power of the high-frequency component was significantly greater at 10 breaths/min than at 20 breaths/min in patients with heart failure, whether expressed in absolute units (P = 0.005) or percentage of total power (P = 0.03). 4. On standing, controlled breathing in patients with heart failure produced less change in high-frequency power (P = 0.054), but the low-frequency/high-frequency ratio at lower respiratory rates was reduced (P = 0.05). In normal subjects, as expected, respiratory rate had a highly significant effect on high-frequency power. Also, in normal subjects there was the expected increase in heart rate low-frequency power (P = 0.04) moving from supine to standing with an increase in the low-frequency/high-frequency ratio (P = 0.003), while in the patients with heart failure this was absent, reflecting blunted cardiovascular reflexes. 5. Systolic blood pressure low- and high-frequency components and their ratio were significantly affected by respiration (P < 0.03) and change in posture (P < 0.03) in both patients with heart failure and normal subjects, with a significant increase in the low-frequency/high-frequency ratio (P = 0.03) on standing in patients with heart failure, indicating that autonomic modulation of blood pressure is still operating in heart failure. 6. Thus, respiratory rate and changes in posture have a significant effect on measurements derived from spectral analysis of heart rate and blood pressure variability. Studies that use power spectral analysis as a measure of sympatho-vagal balance should control for these variables. |
| | |
Authors:
|
J E Sanderson; L Y Yeung; D T Yeung; R L Kay; B Tomlinson; J A Critchley; K S Woo; L Bernardi |
Related Documents
:
|
11408378 - Quantification of mechanical and neural components of vagal baroreflex in humans. 17288748 - Age-related changes in cerebral hemodynamics and their correlations with cardiac autono... 12392838 - Simultaneous heart rate and blood pressure variability analysis. insight into mechanism... 10574418 - Abnormal cardiac autonomic activity and complexity in newly diagnosed and untreated hyp... 19617228 - High-frequency oscillatory ventilation (hfov) and airway pressure release ventilation (... 18416798 - Differences in prevalence of pressure ulcers between the netherlands and germany--assoc... |
Publication Detail:
|
Type: Clinical Trial; Controlled Clinical Trial; Journal Article |
Journal Detail:
|
Title: Clinical science (London, England : 1979) Volume: 91 ISSN: 0143-5221 ISO Abbreviation: Clin. Sci. Publication Date: 1996 Jul |
Date Detail:
|
Created Date: 1996-10-02 Completed Date: 1996-10-02 Revised Date: 2007-11-15 |
Medline Journal Info:
|
Nlm Unique ID: 7905731 Medline TA: Clin Sci (Lond) Country: ENGLAND |
Other Details:
|
Languages: eng Pagination: 35-43 Citation Subset: IM; S |
Affiliation:
|
Department of Medicine, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Adult Aged Autonomic Nervous System / physiopathology Blood Pressure / physiology* Female Heart Failure / physiopathology* Heart Rate / physiology* Humans Male Middle Aged Monitoring, Physiologic Posture / physiology* Respiration / physiology* Signal Processing, Computer-Assisted Supine Position / physiology Systole / physiology |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Acute haemodynamic responses and inhibition of tumour necrosis factor-alpha by pentoxifylline in rat...
Next Document: Ambulatory monitoring of blood pressure disturbs sleep and raises systolic pressure at night in pati...