Time-Courses of the Central Frequencies of Low-Frequency Components of RR Intervals, Systolic and Diastolic Pressure Variabilities in Response to Active Orthostatic Test Conference Paper uri icon

abstract

  • In 25 healthy subjects we assessed the effects provoked by 1-min of active orthostatic test (AOT) on time-courses of central frequencies and powers of low frequency components (CFLF, PLF) of RR (CFLFRR, PLFRR), systolic (CFLFSP, PLFSP) and diastolic (CFLFDP, PLFDP) pressures, estimated by a time-frequency distribution. Ensemble averages of the three PLF-CFLF pairs dynamics depicted an initial sudden change (ISC), followed by a recovery change (RC) and a final sudden change (FSC). The rapid changes were upwards for PLF and downwards for CFLF. Means of the maximal PLF surges and of minimal CFLF falls were greater and smaller (p < 0.01) than their respective control means. Mean correlations of the three PLF-CFLF relations ranged from - 0.95%2b 0.05 to -0.97pm 0.04 in ISC, -0.86pm 0.13 to -0.87pm 0.15 in R C and -0.30pm 0.59 to -0.41pm 0.63 in FSC. In all stages, means of CFLFRR were greater (p < 0.04) than those of CFLFDP. That the patterned responses of the three PLF-CFLF pairs time-courses present rapid initial and final changes, upstrokes for PLF and falls for CFLF, significantly inversely correlated, and the greater level of CFLFRR than CFLFDP, refine the time-course of cardiovascular sympathetic activation in AOT, possibly non-uniform, and suggest that CFLF are trustable quantitative sympathetic measures, with some specificity, CFLFRR for the cardiac and CFLFDP for the vasomotor one. © 2021 Creative Commons.

publication date

  • 2021-01-01