The evaluation of cardiovascular condition based on detecting double channels of pulse transit time simultaneously

Blood pressure (BP) is one of the most important measurement standards of cardiovascular condition. Pulse transit time (PTT), which is the time interval between the peaks of r-wave of Electrocardiogram (ECG) and the peaks of Photoplethysmography (PPG), is promising for non-invasive continuous blood pressure measurement. In this paper, double channels of PTT are obtained. One channel is from heart to fingertip, the other acquired simultaneously is from heart to toe. Using double channels of them simultaneously to evaluate blood pressure is more reliable and accurate than single channel. The evidence is given from correlation aspect. Meanwhile in order to evaluate cardiovascular condition more comprehensively, the damage of lower extremity arteries and lower limb arteriosclerosis should be investigated. A standard of judgment is given by the ratio of pulse wave velocity (PWV) from lower to upper limbs which can be obtained from these two channels as well.