Oscillatory patterns in sympathetic neural discharge and cardiovascular variables during orthostatic stimulus

Raffaello Furlan, Alberto Porta, Fernando Costa, Jens Tank, Lemont Baker, Richard Schiavi, David Robertson, Alberto Malliani, Rogelio Mosqueda-Garcia

Research output: Contribution to journalArticle

Abstract

Background - We tested the hypothesis that a common oscillatory pattern might characterize the rhythmic discharge of muscle sympathetic nerve activity (MSNA) and the spontaneous variability of heart rate and systolic arterial pressure (SAP) during a physiological increase of sympathetic activity induced by the head-up tilt maneuver. Methods and Results - Ten healthy subjects underwent continuous recordings of ECG, intra-arterial pressure, respiratory activity, central venous pressure, and MSNA, both in the recumbent position and during 75°head-up tilt. Venous samplings for catecholamine assessment were obtained at rest and during the fifth minute of tilt. Spectrum and cross-spectrum analyses of R-R interval, SAP, and MSNA variabilities and of respiratory activity provided the low (LF 0.1 Hz) and high frequency (HF, 0.27 Hz) rhythmic components of each signal and assessed their linear relationships compared with the recumbent position, tilt reduced central venous pressure, but blood pressure was unchanged. Hear rate, MSNA, and plasma epinephrine and norepinephrine levels increased, suggesting a marked enhancement of overall sympathetic activity. During tilt, LF(MSNA) increased compared with the level in the supine position; this mirrored similar changes observed in the LF components of R-R interval and SAP variabilities. The increase of LF(MSNA) was proportional to the amount of the sympathetic discharge. The coupling between LF components of MSNA and R-R interval and SAP variabilities was enhanced during tilt compared with rest. Conclusions - During the sympathetic activation induced by tilt, a similar oscillatory pattern based on an increased LP rhythmicity characterized the spontaneous variability of neural sympathetic discharge, R-R interval, and arteria pressure.

Original languageEnglish
Pages (from-to)886-892
Number of pages7
JournalCirculation
Volume101
Issue number8
Publication statusPublished - Feb 29 2000

Keywords

  • Autonomic
  • Catecholamines
  • Nervous system
  • Spectrum analysis
  • Tilt-table test

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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    Furlan, R., Porta, A., Costa, F., Tank, J., Baker, L., Schiavi, R., Robertson, D., Malliani, A., & Mosqueda-Garcia, R. (2000). Oscillatory patterns in sympathetic neural discharge and cardiovascular variables during orthostatic stimulus. Circulation, 101(8), 886-892.