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DOI: 10.1055/s-0038-1633834
A Theoretical Appraisal of the Dependence of Respiratory Sinus Arrhythmia on Gradual Vagal Blockade
Publikationsverlauf
Publikationsdatum:
07. Februar 2018 (online)
Summary
Motivation: The high frequency (HF) indices of heart rate variability (HRV), which reflect the magnitude of respiratory sinus arrhythmia (RSA), have been repeatedly used as measures of cardiac vagal tone. Recent studies, however, have shown experimentally that variations in these indices do not necessarily reflect proportional changes in cardiac parasympathetic outflow.
Objective: The goal of this study was to obtain a physiological-based theoretical evaluation of the relationship between RSA and cardiac vagal tone, which will help explain conflicting experimental results previously published.
Methods: We derived a theoretical model for heart rate (HR) response to gradual vagal blockade. The model implements the integral-pulse-frequency-modulation (IPFM) approach to sinoatrial (SA) node physiology. The level of vagal blockade was simulated by the addition of a cardio-selective muscarinic antagonist.
Results and Conclusion: The derivations of the model lead to a closed set of equations, from which the dependence of the HF indices on the level of vagal blockade is deduced. It is shown that several aspects of the physiological condition may have a substantial effect on this relationship: the level of baseline vagal activity, the relationship between vagal tone and the fluctuations in its traffic, the level of sympathetic activity, etc… Hence, changes in the HF indices of HRV provide a plausible assessment of the changes in cardiac vagal tone only under a specific range of physiological conditions.
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References
- 1 Akselrod S, Gordon D. et al. Hemodynamic regulation: investigation by spectral analysis. Am J Physiol 1985; 249 (04) H867-H875.
- 2 Pomeranz B, Macaulay RJ. et al. Assessment of autonomic function in humans by heart rate spectral analysis. Am J Physiol 1985; 248 (01) H151-H153.
- 3 Goldberger JJ, Challapalli S. et al. Relationship of heart rate variability to parasympathetic effect. Circulation 2001; 103 (15) 1977-83.
- 4 Goldberger JJ, Kim YH. et al. Effect of graded increases in parasympathetic tone on heart rate variability. J Cardiovasc Electrophysiol 1996; 7 (07) 594-602.
- 5 Hyndman BW, Mohn RK. A model of the cardiac pacemaker and its use in decoding the information content of cardiac intervals. Automedica 1975; 1: 239-52.
- 6 Pyetan E, Akselrod S. Do the high frequency indices of HRV provide a faithful assessment of cardiac vagal tone? A critical theoretical evaluation. IEEE Trans Biomed Eng 2003; 50 (06) 777-83.
- 7 Hondeghem LM, Mouton E. et al. Additive effects of acetylcholine released by vagal nerve stimulation on atrial rate. J Appl Physiol 1975; 38 (01) 108-13.
- 8 Rosenblueth A, Simeone FA. The interrelations of vagal and accelerator effects on the cardiac rate. Am J Physiol 1934; 110: 42-55.
- 9 Schulte B, Volz-Zang C. et al. AF-DX 116, a cardioselective muscarinic antagonist in humans: pharmacodynamic and pharmacokinetic properties. Clin Pharmacol Ther 1991; 50 (04) 372-8.
- 10 Foreman JC, Johansen T. Textbook of receptor pharmacology. London: CRC Press; 1996
- 11 Pyetan E, Zoran O, Toledo E, Akselrod S. A theoretical model for the dependency of heart rate on gradual vagal blockade by atropine. Comp in Card 2001; 28: 653-6.
- 12 Akiyama T, Yamazaki T. Adrenergic inhibition of endogenous acetylcholine release on postganglionic cardiac vagal nerve terminals. Cardiovasc Res 2000; 46 (03) 531-8.
- 13 Yang T, Senturia JB. et al. Antecedent sympathetic stimulation alters time course of chronotropic response to vagal stimulation in dogs. Am J Physiol 1994; 266 (04) H1339-H1347.
- 14 Saul JP, Berger RD. et al. Transfer function analysis of the circulation: unique insights into cardiovascular regulation. Am J Physiol 1991; 261 (04) H1231-H1245.
- 15 Malik M, Camm AJ. Components of heart rate variability – what they really mean and what we really measure. Am J Cardiol 1993; 72 (11) 821-2.
- 16 Hedman AE, Hartikainen JE. et al. The high frequency component of heart rate variability reflects cardiac parasympathetic modulation rather than parasympathetic ‘tone’. Acta Physiol Scand 1995; 155 (03) 267-73.
- 17 Hedman AE, Tahvanainen KU. et al. Effect of sympathetic modulation and sympatho-vagal interaction on heart rate variability in anaesthetized dogs. Acta Physiol Scand 1995; 155 (02) 205-14.
- 18 Taylor JA, Myers CW. et al. Sympathetic restraint of respiratory sinus arrhythmia: implications for vagal-cardiac tone assessment in humans. Am J Physiol 2001; 280 (06) H2804-H2814.