Figure 1: Illustration of CAVI measurement. A subject is placed in supine position and electrocardiogram and heart sound are monitored. PWV between heart and ankle is obtained by L/T where L is the distance from the aortic valve to the ankle, and T is the time during which PWV propagates from the aortic valve to the ankle (or the sum of tb and tba in place of t’b and tba, because t’b and tb are theoretically equal: tba is the time between the rise of the brachial pulse wave and the rise of the ankle pulse wave, tb is the time between the aortic valve’s closing sound and the notch of the brachial pulse wave, and t’b is the time between the aortic valve’s opening sound and the rise of the brachial pulse wave).