Instant power spectrum analysis of heart rate variability during orthostatic tilt using a time-/frequency-domain method

Sylvain Jasson, Claire Médigue, Pierre Maison-Blanche, Nicola Montano, Laurent Meyer, Christophe Vermeiren, Pascale Mansier, Philippe Coumel, Alberto Malliani, Bernard Swynghedauw

Research output: Contribution to journalArticlepeer-review


Background: Spectral analysis of heart rate (HR) variability (HRV) requires, as a rule, some level of stationarity and, as a result, is inadequate to quantify biological transients. A time-/frequency-domain method (TF) was developed to obtain an instant spectral power (SP) of HRV during tilt. Methods and Results: HR was recorded by Holter monitoring in volunteers and analyzed with a TF, the smoothed pseudo-Wigner-Ville transformation (SPWVT), with the table inclination randomly set or continuously increased while the table rotated in head-up position. (1) The SPWVT assesses, beat by beat, the instant center frequency (ICF) of the SP. ICF correlates better with instant HR than the ratio of low- (LF) to high-frequency (HF) oscillations. The transient effect of tilt is better characterized as a shift of SP toward lower frequencies than by changes in amplitudes. (2) The method evidences variations of HR from one second to another. During the passage to head-up position, the vagal withdrawal and the sympathetic activation occur nearly simultaneously, as indicated by the instant changes in both LF and HF amplitudes and ICF. (3) The averaged results of the SPWVT give results similar to those previously obtained with autoregressive algorithms. Conclusions: The SPWVT is a new tool to explore HR transitions such as periods before episodes of arrhythmias on a time scale of one beat and allows quantification of an instant frequency index (ICF) that closely reflects the instantaneous relationship between sympathetic and vagal modulations.

Original languageEnglish
Pages (from-to)3521-3526
Number of pages6
Issue number10
Publication statusPublished - Nov 18 1997


  • Electrocardiology
  • Fourier analysis
  • Heart rate
  • Intervals
  • Physiology

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine


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