Spontaneous Baroreflex Sensitivity and Multifractal Hurst Analysis of Heart Rate

Background and Objectives：This study was designed to examine whether the multifractal Hurst exponents of heart rate can estimate activating and deactivating spontaneous baroreflex sensitivity (SBRS). Subjects and Methods： Age and sex matched 24 healthy volunteers were placed in the supine position and head-up tilt position for 30 minutes, and the systolic blood pressure and heart rate were measured in an noninvasive manner. When the RR interval (RRI) sequence and systolic pressure sequence simultaneously increased or decreased for more than three successive beats, the slope of the linear regression line of systolic blood pressure and RR interval sequence was defined as the value of spontaneous baroreflex sensitivity (SBRS). From the RR intervals, very short-term (α range, ≤12 heartbeats), short-term (β range, ≥12 heartbeats), and the multrifractal Hurst exponents were calculated to de-termine the linear correlation.coefficients for SBRS. Results：In the supine position, the linear correlation coeffi-