Three dimensional ballisto- and seismo-cardiography: HIJ wave amplitudes are poorly correlated to maximal systolic force vector

Abstract

Ballistocardiography was recorded in 3-D on a free floating astronaut in space as well as on healthy volunteers participating to the ESA 55(th) and DLR 19(th) parabolic flights campaigns. In this paper we demonstrate further the usefulness of recording and analyzing ballistocardiograms (BCG) in three dimensions. The spatial curves of the displacement, velocity and acceleration vectors are analyzed instead of their individual 2-D components. The maximum magnitude of the force vector is shown to be poorly correlated to the HI and IJ wave amplitude traditionally computed on the longitudinal (feet-to-head) component of acceleration (uni-dimensional BCG). We also suggest that kinetic energy and work are useful parameters to consider for a physiological interpretation of the 3D-BCG. The technique presented is invariant from the axis of representation and provides important novel physiological information. We stress further the need of 3D recordings and analysis techniques for Ballisto- and Seismo-cardiography.

Three dimensional Ballistocardiogram and Seismocardiogram: What do they have in common?

“…The technical details of our procedure are similar to what we have done in previous studies and can be found with more details here [3,4,6].…”

Modification of the mechanical cardiac performance during end-expiratory voluntary apnea recorded with ballistocardiography and seismocardiography

“…Data were exported and processed offline using a specific toolbox written in Matlab version 9.5 R2018b (Mathworks ® ). Further details regarding this methodology have been published previously (Prisk et al 2001, Migeotte et al 2012, Migeotte et al 2016, Hossein et al 2019. P, Q, R, S, and T waves on the ECG were automatically identified and used as reference points for the identification of each cardiac cycle.…”

Cardiovascular changes in parabolic flights assessed by ballistocardiography

“…For each cardiac cycle, ECG, dICG and BCG signals were resampled to a normalized time axis [9], [12]. Shortly: the time axis corresponds to a normalization of the time between two consecutive heart beats from 0 to 1000.…”

“…In previous studies [3], [9], [10], [12], 3D-ballistocardiograms were obtained during a space mission and PF, in order to characterize the BCG signal in µG. The present study inscribes in the continuation of those studies, to further investigate the ballistocardiogram (BCG) in the µG environment, where no other forces than those of cardiac contractions are acting on the body.…”

“…ECG, ICG and BCG were recorded in weightlessness and during two baseline measurements (standing and supine postures). The BCG curves were analyzed through an ensemble averaging method [9], [12] and the I and J peaks of the BCG (Fig.1) were identified. In addition, characteristic peaks of the ECG, ICG and BCG ( Fig.1) were localized and used to compute the following systolic time intervals: RI interval (from the R-peak of the ECG to the I-peak of the BCG), LVET and PEP, which were defined as the BX interval and the RB interval ( Fig.1), respectively.…”