Prediction of Tonic Parasympathetic Cardiac Control Using Respiratory Sinus Arrhythmia: The Need for Respiratory Control

• DOI: 10.1111/j.1469-8986.1991.tb00412.x
• Publication Date: 2007-02-02T21:43:40Z
• Authors: Paul Grossman; John Karemaker; Wouter Wieling
• Keywords: Vagal Tone; Tonic (physiology); Respiratory physiology

ABSTRACT Respiratory sinus arrhythmia (RSA) has received much attention in recent years due to the large body of evidence indicating that variations this phenomenon represent alterations parasympathetic cardiac control. Although it appears respiratory is mediated by vagal mechanisms, extent which well‐known influences (i.e., rate and tidal volume) on (in altering its magnitude) may moderate relationship between RSA tone never been systematically studied. We addressed issue examining intraindividual relationships among magnitude, respiration (rate volume), heart period six healthy male adults after intravenous administration 10 mg propranolol, a beta‐adrenergic blocker. Subjects were exposed various behavioral tasks altered all physiological variables measured. Variations beta blockade assumed be predominantly vagally mediated. Within‐subject regression analyses consistently showed parameters influenced but not tonic beta‐blocked period, suggesting respiratory‐mediated are associated with changes tone. Only when statistically controlled was there reasonable correspondence amplitude, providing support for idea need using amplitude as an index Repeated‐measures variance mean levels across subjects supplemented supported results. These findings point importance controlling index.