• amplitude
  • citation needed] As seen in the figure showing premature ventricular contractions (PVCs), the PPG pulse for the cardiac cycle with the PVC results in lower amplitude blood pressure and a PPG. (wikipedia.org)
  • Patients showed a decrease in the cardiac pulse amplitude caused by reduced cardiac preload during exhalation when the heart is being compressed. (wikipedia.org)
  • skin
  • A PPG is often obtained by using a pulse oximeter which illuminates the skin and measures changes in light absorption. (wikipedia.org)
  • A conventional pulse oximeter monitors the perfusion of blood to the dermis and subcutaneous tissue of the skin. (wikipedia.org)
  • Even though this pressure pulse is somewhat damped by the time it reaches the skin, it is enough to distend the arteries and arterioles in the subcutaneous tissue. (wikipedia.org)
  • If the pulse oximeter is attached without compressing the skin, a pressure pulse can also be seen from the venous plexus, as a small secondary peak. (wikipedia.org)
  • The change in volume caused by the pressure pulse is detected by illuminating the skin with the light from a light-emitting diode (LED) and then measuring the amount of light either transmitted or reflected to a photodiode. (wikipedia.org)
  • The DC component of the signal is attributable to the bulk absorption of the skin tissue, while the AC component is directly attributable to variation in blood volume in the skin caused by the pressure pulse of the cardiac cycle. (wikipedia.org)