Visualizing Cardiac Motion Using Subcutaneously Measured Electrocardiography and Three-Axis Acceleration: Day-to-Day Comparability and Event-Related Changes in Congestive Heart Failure Patients

Abstract

Continuous monitoring of cardiac motion offers valuable insights into heart failure (HF) progression and management. This study explores a method to visualize heart motion trajectories from a novel subcutaneous sensor by integrating electrocardiogram (ECG) data with data from a three-axis accelerometer. By analysing the area covered by those trajectories during the systolic phase changing cardiac function may be assessed quantitatively. During systole the trajectories clearly showed multi-axial mechanical motion of the contracting chest following the cardiac ejection of blood from the left ventricle into the systemic circulation. Consistent daily trajectory patterns were observed in a stable individual on eight different days as their systolic area covered was comparable in size (0.0140mm2 ± 0.054mm2) and orientation. Four Patients that experienced five congestive heart failure events (CHF) showed a reduced systolic plane prior to clinical deterioration as the systolic trajectory area covered was significantly reduced compared to baseline (0.0061mm2 ± 0.0044mm2 at the event versus 0.0158mm2 ± 0.0096mm2 at baseline, p<0.05). Previous research reported qualitatively similar trajectories in healthy volunteers using non-invasive sensors. Additionally, while devices such as other subcutaneous monitoring implants have been evaluated for monitoring ECG and impedance changes in patients with HF, the potential of subcutaneous three-dimensional acceleration measurements remains unexplored. Our findings suggest that this integrated approach could enhance remote monitoring, early detection of decompensation, and personalized treatment strategies for HF patients.