Information transfer through the spontaneous baroreflex in healthy humans.

OBJECTIVES This study assesses the information transfer through the spontaneous baroreflex (i.e. through the pathway linking systolic arterial pressure to heart period) during an experimental condition soliciting baroreflex (i.e. head-up tilt). METHODS The information transfer was calculated as the conditional entropy of heart period given systolic arterial pressure using a mutual neighbor approach and uniform quantization. The information transfer was monitored as a function of the forecasting time k. RESULTS We found that during head-up tilt the information transfer at k = 0 decreased but the rate of rise of information transfer as a function of k was faster. CONCLUSIONS We suggest that the characterization of the information transfer from systolic arterial pressure to heart period might complement the traditional characterization of the spontaneous baroreflex based on transfer function analysis.