Respiratory sinus arrhythmia as a second order system

Abstract

The presented study describes the influence of respiration on heart rate, under controlled respiration conditions. In addition, this study makes a comparison of a simple physical model, the spring-mass system, with the biophysics of respiration. It is possible to use the equations describing the behaviour of the respiratory system, under certain conditions, and analyse them in a way similar to the equations that describe the physical spring-mass system. The results of the heart rate and respiration measurements effected on 10 subjects at various respiration frequencies show us that the heart rate behaves as a second order system within the boundary conditions during a longer period of constant respiration. The results also show that the heart rate behaves as a second order system within the intermediate mode during short time intervals when there is no respiration.

Keywords:

• Respiration
• heart rate
• second order system
• physical model
• ECG

Acknowledgments

The author wishes to thank Mr. Dragoslav Zikich from Ella Institute for Melanoma Treatment and Research, Shiba Medical Center, Tel Hashomer, Israel, for his help in improving the manuscript.