Blood Pressure and Photoplethysmography Signal Pairs Characterization by Dicrotic Notch

The photoplethysmography technique get a rapid traction for cardiovascular noninvasive measurements. As long as its recording source comes from the peripheral blood capillaries the waveform suffers morphological modification with respect to the mechanical blood pressure one. This paper investigated the likeness between blood pressure and photoplethysmography signals by dicrotic notch presence criteria. This fiducial point is an effect of aortic valve closure which creates a seconds rising pressure gradient within cardiovascular network. Therefore, the mechanical quantity trend should be detected in the peripheral side of arterial network as long as its travels along it. A sorted database of 237 patients without cardiovascular disorders were used for the presented analysis. A dedicated algorithm for detecting fiducial points: systolic, diastolic and dicrotic notch was designed. Four signals categories were modeled by sorting the waveform with dicrotic notch presence criterial. A total of 73.31% datasets present a conservation of morphology by concomitant presence or absence of dicrotic notch in both blood pressure and photoplethysmography signals. The rest of the datasets present a modification by the described criteria where an exceptional 2.45% cases were found a dicrotic notch apparition in the peripheral side even if in the upper arterial network this fiducial point was absent.