This Article Full Text Full Text (PDF) Online Supplement All Versions of this Article: 200202-096OCv1 167/2/128    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Jo, J. A. Articles by Khoo, M. C. K. Search for Related Content PubMed PubMed Citation Articles by Jo, J. A. Articles by Khoo, M. C. K.

Model-based Assessment of Autonomic Control in Obstructive Sleep Apnea Syndrome during Sleep

Department of Biomedical Engineering and Department of Medicine, University of Southern California, Los Angeles, California

Correspondence and requests for reprints should be addressed to Michael C. K. Khoo, M.D., Biomedical Engineering Department, OHE-500, University of Southern California, Los Angeles, CA 90080-1451. E-mail: khoo{at}bmsr.usc.edu

Respiration, R-R interval, blood pressure, and other polysomnographic variables were recorded in eight normal subjects and nine patients with untreated obstructive sleep apnea syndrome in wakefulness and sleep. To increase respiratory and cardiovascular variability, a computer-controlled ventilator delivered randomly modulated inspiratory pressures that were superimposed on a baseline continuous positive airway pressure. A mathematical model allowed heart rate variability to be partitioned into a component mediated by respiratory–cardiac coupling and one mediated by the baroreflexes. Respiratory–cardiac coupling gain was lower in patients versus normal subjects (36.9 ± 3.3 versus 66.1 ± 5.6 milliseconds L^-1, p < 0.03). Baroreflex gain in patients was also depressed relative to normal subjects (2.3 ± 0.4 versus 4.9 ± 0.7 milliseconds mm Hg^-1; p < 0.02). Baroreflex gain increased two- to threefold from wakefulness to sleep in normal subjects, but was relatively unaffected by state change in patients. Along with results derived from spectral analysis of cardiovascular variability, these findings confirm previous reports that obstructive sleep apnea syndrome is associated with reduced parasympathetic and elevated sympathetic activity. The model-based approach provides a more precise characterization of heart rate variability that can be employed in conjunction with spectral analysis for the noninvasive detection and assessment of autonomic cardiovascular abnormality in obstructive sleep apnea syndrome.

Key Words: baroreflex sensitivity • cardiovascular control • heart rate variability • mathematical model • respiratory sinus arrhythmia

This article has been cited by other articles:

				K. McConnell, V. K. Somers, T. Kimball, S. Daniels, R. VanDyke, M. Fenchel, A. Cohen, P. Willging, A. Shamsuzzaman, and R. Amin Baroreflex Gain in Children with Obstructive Sleep Apnea Am. J. Respir. Crit. Care Med., July 1, 2009; 180(1): 42 - 48. [Abstract] [Full Text] [PDF]

				S. Ryan, S. Ward, C. Heneghan, and W. T. McNicholas Predictors of Decreased Spontaneous Baroreflex Sensitivity in Obstructive Sleep Apnea Syndrome Chest, April 1, 2007; 131(4): 1100 - 1107. [Abstract] [Full Text] [PDF]

				F. Jurysta, J.-P. Lanquart, P. van de Borne, P.-F. Migeotte, M. Dumont, J.-P. Degaute, and P. Linkowski The link between cardiac autonomic activity and sleep delta power is altered in men with sleep apnea-hypopnea syndrome Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2006; 291(4): R1165 - R1171. [Abstract] [Full Text] [PDF]

				M. R. Bonsignore, G. Parati, G. Insalaco, P. Castiglioni, O. Marrone, S. Romano, A. Salvaggio, G. Mancia, G. Bonsignore, and M. Di Rienzo Baroreflex control of heart rate during sleep in severe obstructive sleep apnoea: effects of acute CPAP Eur. Respir. J., January 1, 2006; 27(1): 128 - 135. [Abstract] [Full Text] [PDF]

				J. A. Jo, A. Blasi, E. Valladares, R. Juarez, A. Baydur, and M. C. K. Khoo Determinants of heart rate variability in obstructive sleep apnea syndrome during wakefulness and sleep Am J Physiol Heart Circ Physiol, March 1, 2005; 288(3): H1103 - H1112. [Abstract] [Full Text] [PDF]

				M. J. Tobin Sleep-Disordered Breathing, Control of Breathing, Respiratory Muscles, Pulmonary Function Testing in AJRCCM 2003 Am. J. Respir. Crit. Care Med., January 15, 2004; 169(2): 254 - 264. [Full Text] [PDF]