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 tb and tba, because tb 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 valves closing sound and the notch of the brachial pulse wave, and tb is the time between the aortic valves opening sound and the rise of the brachial pulse wave).