Abstract.
Respiratory sinus arrhythmia (RSA) estimation is commonly used as a non-invasive index of cardiac vagal tone. To test this relationship, vagal tone was augmented or blocked using atropine. The study was carried out using 14 healthy volunteers, following beta-adrenoceptor blockade (10 mg bisoprolol per os) and during controlled respiration (0.25 Hz) in order to limit the confounding effects of cardiac sympathetic tone and respiration pattern changes. Atropine was slowly infused intravenously over a 30-min period up to a vagolytic cumulative dose of 0.04 mg/kg. The instant vagal tone was compared to the instant RSA value obtained from a time-/frequency-domain analysis of pulse interval (PI). RSA and PI varied in the same direction with an initial increase corresponding to the early vagomimetic effect of atropine followed by a decrease during the vagolytic phase. The comparative percentage fluctuations of RSA and PI over this large vagal tone range indicate that RSA is more sensitive (about twofold) than PI in reflecting fluctuations around the set point. This dissociated behaviour of PI and heart rate variability could be important to our understanding of the circulatory changes that result from fluctuations in vagal inputs to the sinus node.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received after revision: 29 September 2000
Electronic Publication
Rights and permissions
About this article
Cite this article
Médigue, C., Girard, A., Laude, D. et al. Relationship between pulse interval and respiratory sinus arrhythmia: a time- and frequency-domain analysis of the effects of atropine. Pflügers Arch - Eur J Physiol 441, 650–655 (2001). https://doi.org/10.1007/s004240000486
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s004240000486