The seismocardiogram (SCG) is the recording of chest vibrations caused by the heartbeats and SCG systems with sternal sensors can identify the opening and closure of the cardiac valves. We recently developed wearable systems to simultaneously record one-lead electrocardiogram (ECG) and SCG with sensors placed at different body sites. This work aims to describe possible gender differences in HRV and cardiac mechanics from sternal SCG measures in healthy individuals.
We enrolled 30 young adults (15 males, 15 females) and recorded the ECG and sternal SCG in the participants sitting at rest. We selected 6 minutes of steady-state recording and derived HRV autonomic indices from the ECG and two indices of cardiac mechanics from the sternal SCG: the pre-ejection period (PEP) and left-ventricle ejection time (LVET). The HRV analysis revealed significantly higher respiratory vagal modulations of heart rate and lower indices of cardiac sympathovagal balance in females. The SCG analysis showed a significantly shorter PEP in females. Therefore, our HRV
results confirm the higher cardiac vagal modulation in phase with respiration that previous studies reported in females. However, they also indicate, for the first time, a higher cardiac contractility, quantified by the lower PEP, in females.
