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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Clinical autonomic research 7 (1997), S. 131-135 
    ISSN: 1619-1560
    Keywords: heart rate variability ; blood pressure waves ; deep breathing ; spectral analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The measurement of heart rate variation during forced breathing (HRDB) is a well-known clinical test of parasympathetic function. It is known that normal values of HRDB are strongly dependent on age. However, little is known about other physiological factors that may lead to reduced HRDB values that may mimic parasympathetic failure. Thirty-two normal subjects (age 56.7±12.4 years) and 32 neurological patients with pathological autonomic test findings (age 57.9±10.2) were studied. Oscillations in heart rate and in mean arterial blood pressure were recorded in the supine position during forced breathing (6 cycles/min) using the Finapres monitor. Amplitudes of heart rate and blood pressure waves at 6 cycles/min (HR6 and ABP6) as well as gain values (Gain6=HR6/ABP6) and phase differences ({ie131-1}) between HR and ABP waves were calculated by means of spectral analysis. The mean (±SD) HR6 in normal subjects was 6.34±3.36 cycles/min with a mean ABP6 of 5.11±2.49 mmHg. HR6 correlated significantly with age (r=−0.426) and with ABP6 (r=0.602). No significant correlation was found between HR6 and mean blood pressure, mean heart rate or sex. From 24 patients with pathological findings in the classical HRDB value, only nine could be classified as pathological when the effect of ABP6 was considered. In conclusion, ABP variations significantly influence the amplitude of heart rate variations during forced breathing. We interpret these findings in terms of a baroreflex mechanism of HRDB including both vagal and sympathetic efferents. Normal reference value tables for clinical HRDB studies should not only consider age but also the amplitude of blood pressure variations.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Clinical autonomic research 7 (1997), S. 311-314 
    ISSN: 1619-1560
    Keywords: idiopathic Parkinson's disease ; sympathetic dysfunction ; autonomic evaluation ; spectral analysis ; baroreflex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Standard autonomic tests (heart rate response to deep breathing-HR db , heart rate and systolic blood pressure response to tilt-ΔHR and ΔSBP) and spectral analysis of heart rate and arterial blood pressure and their transfer function (for the mid-frequency band a measure of baroreflex sensitivity) were performed in 20 patients with idiopathic Parkinson's disease (IPD) and 20 age-matched controls. Patients showed significantly diminished ΔSBP, and reduced sympathetic vasomotor and cardiomotor outflow (diminished Mayer waves), consistent with an alteration of the efferent arc of the baroreflex. These results were only significant in long-standing IPD (IPD-1, 〉5 years), whereas patients with short disease duration (IPD-s, 〈5 years) showed values comparable to controls. Respiratory-related heart rate variability was slightly reduced in IPD-1 but this was mainly due to diminished respiratory effort, indicated by low respiratoryrelated blood pressure variability. We conclude that autonomic abnormalities are only present in long-standing IPD and consist in reduced sympathetic vasomotor and cardiomotor outflow.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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