[01] José Luis Hernández Cáceres, Biomedical Sciences Department, School of Medicine and Allied Health Sciences, University of the Gambia (UTG), Banjul, the Gambia;Center for Cybernetics Applications to Medicine, Havana Medical University, Havana, Cuba. [02] Emmanuel Syed Hasan, Physics Department, Division of Physical and Natural Sciences, School of Arts and Sciences, University of the Gambia (UTG), Brikama, the Gambia.

To potentiate the diagnostic capacity of photoplethysmographic (PPG) signals is a major challenge for both researchers and clinicians. We introduced the “waveform transit time” (TT_W) as a new first derivative related index to assess pulse wave transit time on the basis of the analysis of a PPG waveform. Numerical simulation revealed that that TTW is a good proxy for the delay between incident and reflected waves in a model PPG waveform. A study was conducted on a sample of 230 PPG recordings obtained from presumably healthy subjects (8 to 89 years of age). TT_W analysis revealed that TT_W linearly decreases with age (TT_W = -1.5773*age+207.26; R = -0.82). Lumped data regression confirmed the linear trend, but also revealed heteroskedasticity, with standard deviation decreasing from 25 ms at the age of 20 down to 15 ms at the age of 60. Assuming that the reflected wave traveled an additional pathway of 1 meter as average in an adult population, an attempt was made to predict “normative” data for pulse wave velocity (PWV) based on our results. The obtained prediction for different age groups was in excellent agreement with published normative data for PWV. The plausibility of our results and the fact that TT_W estimation requires minimal expertise, provide further support to the idea of PPG as a promising source for PWV assessment not only in research laboratories but also in primary health care facilities.

Photoplethysmographic Signal, Transit Time, Pulse Wave Velocity, Cardiovascular Ageing

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