Direct Gravity-Induced Modulation of Cardiac Conduction Pathways Evidenced Through Propagation Features in Electrophysiological Mapping

Abstract

The heart’s electrical function is known to adapt to physiological demands, but the mechanisms by which gravitational force may modulate conduction remain unexplored. Understanding this could reshape interpretations of cardiac electrical behaviour in altered gravity, such as during long-term spaceflight. Microgravity induces changes in cardiac morphology, fluid distribution and autonomic regulation, linked to rhythm disturbances including QT prolongation and sudden cardiac death. Current explanations remain largely indirect, attributing electrical changes to haemodynamic or autonomic factors. Conventional ECG lacks the spatial resolution to determine whether gravity directly affects propagation. Here, we investigate whether gravitational loading directly alters cardiac conduction by examining posture-driven shifts in gravitational vectors in a controlled ground-based model. We developed a high-density electrode array to perform localised body surface potential mapping, enabling extraction of conduction-sensitive propagation features. Using machine learning classification, we demonstrate that postural changes can be reliably detected based solely on these features, something not achievable with standard ECG metrics. These results suggest that cardiac conduction is not merely responding to systemic physiological feedback but is sensitive to changes in gravitational orientation through its effects on the spatial configuration of conductive myocardial tissue. This suggests a previously unrecognised mechanism by which gravity can directly influence cardiac electrophysiology. Our findings highlight a limitation in current cardiac monitoring systems, particularly in extreme environments such as space. By identifying gravity-sensitive features of cardiac conduction, this work opens a path to new diagnostic tools and deeper physiological understanding of the heart’s adaptation to altered gravitational states.