SHORT COMMUNICATION
Baroreflex Sensitivity as an
Individual Characteristic Feature
M. JÍRA, E. ZÁVODNÁ, N. HONZÍKOVÁ, Z. NOVÁKOVÁ,
B. FIŠER
Department of Physiology, Faculty of Medicine, Masaryk
University, Brno, Czech Republic
Received June 13, 2005
Accepted July 28, 2005
On-line available August 5, 2005
Summary
The reproducibility of baroreflex sensitivity (BRS in ms/mmHg;
BRSf in mHz/mmHg) determined with respect to the coherence
between the variability in systolic blood pressure (SBP) and
inter-beat intervals (IBI) or heart rate (HR) was tested. SBP
and IBI were recorded beat-to-beat for 5 min (Finapres,
breathing at 0.33 Hz) in 116 subjects (aged 19-24 years) sitting
at rest three times in periods of one week. BRS and BRSf was
determined by a cross-spectral method in a frequency range of
0.067-0.133 Hz. Eight indices were evaluated: BRS0.1Hz/BRSf0.1Hz
- the value at a frequency of 0.1 Hz; BRSCOHmax/BRSfCOHmax - the
value at maximum coherence; BRSWcoh/BRSfWcoh - weighted value
with respect to coherence values in the whole frequency range;
BRSWPcoh/BRSWPcoh - weighted value with respect to coherence for
frequencies with coherence above 0.5. All indices revealed a
lower intraindividual than interindividual variability
(p<0.001). The individual mean values of BRS or BRSf correlated
(p<0.001) with standard deviation of their individual values for
all indices. Baroreflex sensitivity is an individual
characteristic feature with the highest reproducibility at its
low values in spite of its resting variation. Reproducibility is
not influenced by modification of the spectral method used.
Key words
Baroreflex sensitivity • Reproducibility • Interindividual
variability
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