BigHeart: Mapping connectivity in the adult human heart at the micron scale

Abstract

The human heart depends on coordinated muscular, electrical, vascular, lymphatic, and neural systems, but their three-dimensional relationships remain unresolved at microscopic resolution across an intact adult organ. Using hierarchical phase-contrast tomography, we generated a continuous three-dimensional structural reference of a whole adult human heart at 8.01 micrometer isotropic voxel size, without sectioning or staining. Organ-wide imaging revealed hierarchical myocardial architecture, and quantitative orientation analysis identified regional differences in myocardial cell aggregate organization. The atrioventricular conduction axis was traced into a distinct subendocardial Purkinje network interfacing with working myocardium. Integrated segmentation showed that coronary vessels, lymphatic collectors, and autonomic nerves occupy shared epicardial corridors. This publicly accessible dataset integrates cardiac systems within a common spatial framework for anatomy, computational modeling, and future molecular atlases.