Abstract
The rate of convergence of Walsh functions and sine functions to recorded blood pressure waves was determined to evaluate the applicability of Walsh functions for spectral analysis of pulsatile blood pressure. The advantages of Walsh function series for such analysis are that their calculation is much faster and can be performed on small computers.
Walsh function series were computed for blood pressure waves recorded from anesthetized dogs. It was found that 13 terms of the Walsh series represented 98% of the power in the wave. An equal number of Fourier terms contained 99% of the power. Angiotensin induced hypertension produced an increase in the amplitude of the lower terms of the Walsh function series, showing that this method is sensitive to physiologic alterations in blood pressure. It is concluded that Walsh functions are a computationally faster alternative to sine functions for spectral analysis of pulsatile blood pressure.
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Supported by a New York University School of Medicine Honors Program Summer Research Fellowship funded by PHS General Research Grant FR 05399-10 and the John A. Hartford Foundation.
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Shapiro, J.B., Reich, T. Walsh functions for simplifying computation of blood pressure wave power spectra. Ann Biomed Eng 2, 265–273 (1974). https://doi.org/10.1007/BF02368497
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DOI: https://doi.org/10.1007/BF02368497