Phase-averaged characterization of respiratory sinus arrhythmia pattern

• Published in: American journal of physiology. Heart and circulatory physiology Vol. 288; no. 2; pp. H504 - H510
• Main Authors: Gilad, O, Swenne, C. A, Davrath, L. R, Akselrod, S
• Format: Journal Article
• Language: English
• Published: United States 01.02.2005
• Subjects: Adult; Arrhythmia, Sinus - physiopathology; Autonomic Nervous System - physiology; Female; Heart Rate - physiology; Humans; Male; Respiratory Mechanics - physiology
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.00366.2004

1 Raymond and Beverly Sackler Faculty of Exact Sciences, Abramson Center of Medical Physics, Tel Aviv University, Tel Aviv, Israel; and 2 Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands Submitted 26 April 2004 ; accepted in final form 15 September 2004 A method for the accurate time-domain characterization of respiratory sinus arrhythmia (RSA) pattern is presented and applied to two groups of healthy subjects to lay the baseline of RSA patterns and to underlay their features: response to standing, stability in successive recordings, and individuality of the shape of RSA pattern. RSA pattern is evaluated by selective averaging of heart rate (HR) changes from multiple respiratory cycles over the respiratory phase and represents the complete modulating function of HR by respiration. The RSA pattern is evaluated with free respiration and even in cases of severe arrhythmia. Estimation error is 6–8% in magnitude, phase resolution is 0.2 rad, and sensitivity margin for respiratory-related HR variability (HRV) components is 1%. RSA magnitude, phase lag, and expiration-to-inspiration time ratio are derived in addition to the entire pattern. In a group of 10 healthy young adults, a phase lag difference of 11.4 ± 8.5% (mean ± SD, P < 0.004) was observed between supine and standing postures, possibly ascribed to breathing mechanics. A second group of 15 healthy young adults at supine rest showed stability of the RSA pattern in successive recordings (several weeks apart) as well as individuality among subjects. This may suggest a nonscalar individual long-term index for cardiorespiratory coupling. The method is complementary to the existing statistical and spectral methods. It allows the complete characterization of the primary RSA components and may provide new insight into the effects of vagal activity and changes in clinical conditions. autonomic function; heart rate variability; integral pulse frequency modulation; modulating function Address for reprint requests and other correspondence: S. Akselrod, Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Abramson Center for Medical Physics, Tel Aviv Univ., Tel Aviv, Israel 69978 ( solange{at}post.tau.ac.il )