A laser Doppler approach to cardiac motion monitoring: effects of surface and measurement position

In this paper we present a novel, non-invasive measurement system for optical monitoring of the cardiac rate. This measurement method, called vibrocardiography (VCG), is based on the use of a laser Doppler vibrometer for the measurement of the velocity of displacement of the skin in correspondence of the chest wall. We report the typical VCG signals measured on 4 healthy subject and in particular, we investigated the effect on the signal of the measurement position respect to the chest wall as well as the effect of the surface characteristics on the measured signal.