Physiol. Res. 55: 349-351, 2006

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
 


© 2006 by the Institute of Physiology, Czech Academy of Sciences