Wave Separation and Waveform Analysis
Wave separation is the calculation of forward and reflected pressure and flow waves. The calculation can be performed in the time domain (Chap. 12). Forward pressure and flow waves are similar in shape, and the reflected pressure and flow waves are also similar in shape, but the reflected flow wave is inverted with respect to the reflected pressure wave. This difference in polarity of the reflected waves leads to differences in the shape of the measured pressure and flow waves. The Reflection Magnitude is the ratio of the amplitudes of reflected and forward wave, and the Reflection Index is the amplitude ratio of reflected wave and measured pressure wave. In waveform analysis the pressure wave shape is analyzed in terms of Augmentation Index, AIx, defined as Augmented Pressure over Pulse Pressure and the return time of the reflected wave, as estimated from the inflection point in measured pressure.
KeywordsWave separation Forward pressure Reflected pressure Reflection magnitude Reflection index Augmentation index Inflection point