Figure 1

(a) Schematic representation of the augmentation index. The augmentation index is the ratio of augmentation to pulse pressure. (b, c) Typical ascending aortic pressure waveforms in normal aortic circulation. (b) 4 years old, body height 99.5 cm, augmentation index 12%. The reflection wave returns to the ascending aorta before aortic valve closure and enhances the left ventricular load by increasing aortic pressure in systole. (c) 12 years old, body height 163 cm, augmentation index −52%. The reflection wave returns to the ascending aorta after aortic valve closure and thus enhances coronary blood flow.