Detection of the baroreflex function changes during the 30-minute supine rest by the Poincaré plot-based method

Using two Poincare plots to analyze concordant systolic blood pressure (SBP) and RR interval changes, we have developed a novel method for quantifying baroreflex function (the ppBR method). The ppBR method quantifies the short-(BRS1), long-term (BRS2), and total baroreflex sensitivity (BRST), and baroreflex effectiveness (BRE) for increasing (uu) and decreasing (dd) values of SBP and RR intervals. The ppBR also explores the asymmetrical features of the baroreflex separately for uu and dd SBP-RR intervals interactions. The 30-minute resting beat-to-beat recordings of SBP and RR intervals from ECG from 156 healthy young adults were cut into thirty 1-minute windows. The ppBR method demonstrated asymmetrical features of BRS1 and BRE, and found that BRS2 and BRST gradually increased with the duration of the supine rest. The ppBR method visualizes subtle changes in the relationship between SBP and RR intervals caused by the cardiovascular adaptation to the rest in the supine position.