Figure 3

Augmentation Index. The interaction between the incident pulse wave and the reflected pulse wave, which is generated by the arterial resistance, is expressed by the augmentation index, which is the amount of pulse wave induced only by arterial resistance. In the figure, the upper arrow indicates the first systolic peak (incident wave), while the lower arrow indicates the second systolic peak (reflected wave). The ratio between the reflected wave/incident wave × 100 is the augmentation index.