SPECTRAL-ANALYSIS OF SYSTOLIC BLOOD-PRESSURE AND HEART-RATE OSCILLATIONS RELATED TO RESPIRATION

1. Non-invasive assessment of short-term systolic blood pressure (SBP) and heart rate (HR) variability was obtained with the plethysmographi c finger blood pressure measurement device. Respiration was measured w ith a respiratory inductive plethysmograph, which was calibrated prior to each study. 2. The effects of breathing pattern on the respiratory (high frequency, HF) component of the SBP or HR spectrum were analyse d by Fourier transform. 3. Our quantification of the changes in the HF (respiratory) peak of the HR or SBP spectrum with changes in tidal vo lume (V-T) and breathing frequency (BF) indicates that the modulus of this component may be predicted for any combination of depth and frequ ency of breathing. 4. The modulus of this HF component for the HR or S BP spectrum was linearly related to the respiratory sinus arrhythmia ( RSA) or to the SBP oscillation related to respiration.