Temporal Changes of Fiducial Seismocardiogram Points Due to Different Sensor Placements on the Chest

This research focused on morphology changes due to sensor placement of the seismocardiogram (SCG). Data was recorded from seven male subjects, in supine position, accelerometers were placed in both vertical (V) and horizontal (HL) positions leading from the xiphoid process. The subjects were asked to perform a Valsalva maneuver and signals were analyzed before and after. Features of aortic valve closing (AC), aortic valve opening (AO) and the mitral valve closing (MC), were annotated. The features were performed for five cardiac cycles for every participant. The average of absolute percentage changes over the seven subjects was calculated for both V and HL cases. The correlation coefficients between all signals were also calculated to quantify the linear relationships. Moving ¼ of the length of the sternum changes MC point an average of 3.2%, AO annotation 2.6% but AC did not change. At the suprasternal notch annotations change significantly. HL array placement near apex showed negative correlation and inversion of peaks. It was found that the signal morphology does depend on the placement upon the sternum, however, placement differences might not induce significant changes in the timing fiducial points of SCG.