Abstract
Computer simulations were carried out to appraise three new criteria for the estimation of baroreflex sensitivity (BRS) using the tranfer function method. The major goal was to identify a computation procedure able to overcome the intrinsic limitations of the classical coherence criterion. Four representative shapes of the gain function and three different average agains (2, 5 and 8 ms(mmHg)−1) in the lowfrequency (LF) band (0.04–0.15 Hz) were considered. The signal-to-noise ratio was made to vary so that the peak coherence in the LF band changed from 0.15 to 0.9 All simulation parameters were derived from previous observations in healthy subjects and heart disease patients. The error of the estimated gain function was obtained from its confidence interval. BRS was computed as average gain in the LF band: (a) including in the average only those points having error≤ threshold (criterion 1, C1); (b) calculating the mean error in the band and accepting BRS measurements only when this error was ≤ threshold (criterion 2, C2); (c) including in the average all points, regardless of the error (criterion 3, C3). The three criteria were compared in terms of measurability (percentage of measured BRS) and accuracy (bias and SD of BRS). Using C1 and C2, measureability dropped to 10% when the peak cohrence in the LF band decreased, respectively, to 0.18–0.41 and to 0.26–0.53, depending on the shape and strength of the gain. In this condition (lower bound of measureability), worst bias and SD (average gain: 8 ms(mmHg)−1) were, respectively, 0.8 ms(mmHg)−1 and 3.3 ms(mmHg)−1 (C1), and 0.1 ms(mmHg)−1 and 1.0 ms(mmHg)−1 (C2), C3, by definition, always ensured 100% measurability and showed bias and SD comparable with, or even lower than, C1 and C2, within the common range of measurable BRS. In the extreme condition of 0.15 coherence, bias and SD were, respectively, 1.7 ms(mmHg)−1 and 2.3 ms(mmHg)−1 (average gain: 8 ms(mmHg)−1). Hence, error checking (C1 and C2) dramatically reduced measurability and did not improve accuracy of BRS measurements compared with performing no error check (C3). In conditions of low signal-to-noise ratio and/or impaired baroreflex gain, leading to markedly reduced coherence, the simple average of the gain function in the LF band allows BRS to be estimated with accuracy adequate for clinical purposes.
Similar content being viewed by others
References
Basselli, G., Cerutti, S., Civardi, S., Malliani, A., andPagani, M. (1988): ‘Carchovascular variability signals: toward the identification of a closed-loop model of the neural control mechanisms’,IEEE Trans. Biomed. Eng.,35, pp. 1033–1046
Bertram, D., Barrés, C., Cuisinaud, D., andJulien, C. (1998): The arterial baroreceptor reflex exhibits positive feedback properties at the frequency of Mayer waves’,J. Physiol.,513.1, pp. 251–261
De Boer, R. W., Karemaker, J. M., andStrakee, J. (1987): ‘Hentodynamic fluctuations and baroreflex sensitivity in humans: a beat-to-beat mode’.Am. J. Physiol.,253, pp. 680–689
La Rovere, M. T., Bigger, J. T., Marcus, F. I., Mortara, A., andSchwartz, P. J. for the ATRAMI Investigators (1998): ‘Barbreflex sensitivity and heart rate variability in prediction of total cardiac moratility after myocardial infarction’,Lancet,351, pp. 478–484
Mandel, J. (1991): Evaluations and control of measurments’ (Marcel Dekker, Inc., New York, 1991)
Mortara, A., La Rovere, M. T., Pinna, G. D., Parziale, P., Maestri, R., Capomolia, S., Opasich, C., Cobelli, F., andTavazzi, L. (1997): ‘Depressed arterial baroreflex sensitivity and not reduced heart rate variability identifies patient with chronic heart failure and nonsustained ventricular tachycardia: the effect of high ventricular filliing pressure’,Am. Heart. J.,13, pp. 879–888
Pinna, G. D., andMaestri, R. (2001): ‘Reliability of transfer function estimates in cardiovascular variability analysis’,Med. Biol. Eng. Comput.,39, pp. 338–347
Polosa, C. (1984): ‘Central nervous system origin of some type of Meyer waves' inMiyakawa, K., Koepchen, H. P., andPolosa, C. (Eds.): ‘Mechanisms of blood pressure waves’ (Springer-Verlag. Tokyo, 1984), pp. 277–292
Priestley, M. B. (1981): ‘Spectral analysis and times series’ (Academic Press, London, 1981).
Radaelli, A., Perlangeli, S., Cerutti, M. C., Mircoli, L., Mori, I., Boselli, L., Bonaita, M., Terzoli, L., Candotti, G., Signorini, G. andFerrari, A. U. (1999): ‘Altered blood pressure variability in patients with congestive heart failure’.J. Hypertens.,17, pp. 1905–1910.
Robbe, H. W. J., Mulder, L. J. M., Ruddel, H., Langewitz, W. A., Veldman, J. B. P., andMulder, G. (1987): ‘Assessment of baroreceptor reflex sensitivity by means of spectral analysis’,Hypertension,10, pp. 538–543.
Sleight, P., La Rovere, M. T., Mortara, A., Pinna, G. D., Maestri, R., Leuzzi, S., Bianchini, B., Tavazzi, L., andBernardi, L. (1995): ‘Physiology and pathophysiology of heart rate and blood pressure variability and pathophysiology of heart analysis largely an index of baroreflex gain?’,Clin. Sci.,88, pp. 103–109.
Taylor, J. A., andEckberg, D. L. (1995): ‘Fundamental relations between short-term RR interval and arterial pressure oscillations in humans’,Circulation,93 pp. 1527–1532.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Pinna, G.D., Maestri, R. New criteria for estimating baroreflex sensitivity using the transfer function method. Med. Biol. Eng. Comput. 40, 79–84 (2002). https://doi.org/10.1007/BF02347699
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02347699