Time-independent indices of circadian blood pressure and heart rate regulation from ambulatory blood pressure monitoring

Abstract

These results indicate that theta can detect differences in circadian arterial pressure profile that could assess the efficiency of arterial pressure (and heart rate) regulatory mechanisms over the whole day in individuals with different arterial pressure levels. Theta can be easily obtained under ambulatory conditions without any assumption on underlying mathematical models or operator-dependent attribution of arterial pressure and heart rate values to daytime or night-time subperiods. Cross-sectional and prospective studies relating theta to target organ damage and cardiovascular outcomes will inform us about its clinical relevance.

Age-related changes in phase-space distribution of ABPM data in normotensive and hypertensive patients

“…Recently Pizzinelli et al, in a retrospective study of 676 ABPM quantified the R-R interval-systolic blood pressure relation using a non-parametric method to yield a measure of the slope, called the "theta index". Although not quantitatively comparable with AARI, qualitatively similar results have been reported, which is to say that the "theta index" was steeper in the young and in the normotensive group (Pizzinelli et al, 2009). 3).…”