Non-invasive technique for analysis of feedback relationship between heart rate and beat-to-beat blood pressure fluctuations

The authors developed a noninvasive technique for analyzing the feedback relationship between short-term fluctuations in blood pressure and heart rate in human subjects. Beat-to-beat fluctuations of blood pressure and R-R interval were monitored for several minutes with a new type of blood pressure measuring device, which can detect the pulsations of brachial artery of human subjects. The recorded R-R intervals and the beat-to-beat blood pressure were fitted to a multivariate autoregressive model, according to Akaike´s (1969) method. Impulse response function and the relative power contribution between the two variables clearly demonstrated the mode of feedback regulations between the two. This may provide a convenient tool for assessing baroreflex in daily life of healthy subjects and in patients with various diseases