摘要：Photoplethysmography (PPG) is a non-invasive, simple and well-known physiological method for recording and monitoring blood volume pulse, but still there are many unknown issues concerning this method such as individual variability and repeatability of the PPG waveform. In our study we recorded two PPG signals (from the radial artery and from the finger) several times in resting conditions to evaluate the individual repeatability of PPG wave shape. Arbitrary amplitudes of incisura and maximum of dicrotic notch and time from foot to anacrotic maximum had the greatest repeatability among PPG wave shape parameters in both radial artery and finger. Maximum of the first derivative in the anacrotic phase in the PPG waveform showed the highest variability. A possible explanation for the existing individual variability of PPG parameters might be temporal and spatial summation of fluctuations of heart cycle length and changes of peripheral resistance in magistral artery and microcirculatory vessels
