Nonlinear methods of biosignal analysis in assessing terbutaline-induced heart rate and blood pressure changes

Am J Physiol Heart Circ Physiol. 2002 Feb;282(2):H773-83. doi: 10.1152/ajpheart.00559.2001.

Abstract

The aim of this study was to characterize how different nonlinear methods characterize heart rate and blood pressure dynamics in healthy subjects at rest. The randomized, placebo-controlled crossover study with intravenous terbutaline was designed to induce four different stationary states of cardiovascular regulation system. The R-R interval, systolic arterial blood pressure, and heart rate time series were analyzed with a set of methods including approximate entropy, sample entropy, Lempel-Ziv entropy, symbol dynamic entropy, cross-entropy, correlation dimension, fractal dimensions, and stationarity test. Results indicate that R-R interval and systolic arterial pressure subsystems are mutually connected but have different dynamic properties. In the drug-free state the subsystems share many common features. When the strength of the baroreflex feedback loop is modified with terbutaline, R-R interval and systolic blood pressure lose mutual synchrony and drift toward their inherent state of operation. In this state the R-R interval system is rather complex and irregular, but the blood pressure system is much simpler than in the drug-free state.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Pressure / drug effects*
  • Cross-Over Studies
  • Entropy
  • Heart Rate / drug effects*
  • Humans
  • Male
  • Models, Cardiovascular*
  • Nonlinear Dynamics
  • Sympathomimetics / administration & dosage*
  • Terbutaline / administration & dosage*

Substances

  • Sympathomimetics
  • Terbutaline