3D-ballistocardiography in microgravity: Comparison with ground based recordings

3D-Ballistocardiograms ECG and Impedancecardiograms (ICG) were recorded on 5 healthy volunteers participating to the European Space Agency (ESA) 57^th parabolic flights campaigns. Comparisons are made between the baseline recordings performed on the ground and the recordings made during the microgravity phases of a parabolic flight. The spatial curves of the displacement, velocity and acceleration vectors, instead of their individual components are used to compute the magnitude of the force vector, kinetic energy and work during the cardiac cycle. Our hypothesis is that the 3D-BCG provides parameters correlated with the timings of ejection (PEP, LVET). Although our subject population is limited (N=5), this is the first study of BCG to be performed with N>1. Our results suggest that microgravity decrease the complexity of the 3D displacement curve and that peaks in curvature are consistently present in microgravity and on the ground. However they do not seem to be perfectly related to the classical cardiac ejection timings from ICG.