Left ventricular trabeculation in Hominidae : divergence of the human cardiac phenotype

DATA AVAILABILITY : The data that support the findings of this study are available in Figshare repository with the identifiers: https://doi.org/10.6084/m9.figshare.24274852 and https://doi.org/10.6084/m9.figshare.24274855.Although the gross morphology of the heart is conserved across mammals, subtle interspecific variations exist in the cardiac phenotype, which may reflect evolutionary divergence among closely-related species. Here, we compare the left ventricle (LV) across all extant members of the Hominidae taxon, using 2D echocardiography, to gain insight into the evolution of the human heart. We present compelling evidence that the human LV has diverged away from a more trabeculated phenotype present in all other great apes, towards a ventricular wall with proportionally greater compact myocardium, which was corroborated by post-mortem chimpanzee (Pan troglodytes) hearts. Speckle-tracking echocardiographic analyses identified a negative curvilinear relationship between the degree of trabeculation and LV systolic twist, revealing lower rotational mechanics in the trabeculated non-human great ape LV. This divergent evolution of the human heart may have facilitated the augmentation of cardiac output to support the metabolic and thermoregulatory demands of the human ecological niche.The Natural Sciences and Engineering Research Council and the Canadian Foundation for Innovation.https://www.nature.com/commsbio/hj2024Centre for Veterinary Wildlife StudiesSDG-03:Good heatlh and well-bein