title: Revisiting the potential of time-domain indexes in short-term HRV analysis.
abstract: In the context of HRV analysis, we evaluated the information content of two measures that can easily be derived from the classical RR time-domain indexes. The two measures are: 1) the ratio sd/rmssd, where sd is the RR standard deviation and rmssd is the root mean square of squared differences of consecutive RR beats; and 2) the ratio sd2/sd1, where sd2 and sd1 are extracted from the Poincaré plot and represent the transversal and longitudinal dispersion of the cloud of points (RR(i),RR(i)(+1)). We compared the performance of the two measures with that of the classical LF/HF ratio in a group of healthy subjects who underwent a 70 degrees upright tilt test. The goodness of the results obtained by the two measures, the simplicity of their calculation and their applicability free from a priori assumptions on the characteristics of the data are proposed to the attention of the community involved in the HRV analysis as a possible alternative to the LF/HF ratio.
authors.affiliation: Institute of Clinical Physiology, National Research Council, Pisa, Italy. balocchi@ifccnr.it
authors.forename: Rita
authors.initials: R
authors.lastname: Balocchi
authors.forename: Federico
authors.initials: F
authors.lastname: Cantini
authors.forename: Maurizio
authors.initials: M
authors.lastname: Varanini
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Raimondi
authors.forename: Jacopo M
authors.initials: JM
authors.lastname: Legramante
authors.forename: Alberto
authors.initials: A
authors.lastname: Macerata
mesh_terms: D000328:Adult; D000465:Algorithms; D001683:Biological Clocks / Q000502:physiology*; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D009991:Oscillometry / Q000379:methods; D012189:Retrospective Studies; D013997:Time Factors