Trabecular Architecture Determines Impulse Propagation Through the Early Embryonic Mouse Heart

0503876 - FGÚ 2020 RIV CH eng J - Journal Article
Olejníčková, Veronika - Šaňková, Barbora - Sedmera, David - Janáček, Jiří
Trabecular Architecture Determines Impulse Propagation Through the Early Embryonic Mouse Heart.
Frontiers in Physiology. Roč. 9, Jan 8 (2019), č. článku 1876. ISSN 1664-042X. E-ISSN 1664-042X
R&D Projects: GA ČR(CZ) GA13-12412S; GA MŠMT(CZ) LTC17023; GA MŠMT(CZ) LM2015062; GA ČR(CZ) GA18-03461S
Research Infrastructure: Czech-BioImaging - 90062
Institutional support: RVO:67985823
Keywords : cardiac conduction * mouse embryo * mathematical modeling * trabeculation * optical mapping
OECD category: Anatomy and morphology (plant science to be 1.6)
Impact factor: 3.367, year: 2019
Method of publishing: Open access
https://doi.org/10.3389/fphys.2018.01876

Most embryonic ventricular cardiomyocytes are quite uniform, in contrast to the adult heart, where the specialized ventricular conduction system is molecularly and functionally distinct from the working myocardium. We thus hypothesized that the preferential conduction pathway within the embryonic ventricle could be dictated by trabecular geometry. Mouse embryonic hearts of the Nkx2.5:eGFP strain between ED9.5 and ED14.5 were cleared and imaged whole mount by confocal microscopy, and reconstructed in 3D at 3.4 mu m isotropic voxel size. The local orientation of the trabeculae, responsible for the anisotropic spreading of the signal, was characterized using spatially homogenized tensors (3 x 3 matrices) calculated from the trabecular skeleton. Activation maps were simulated assuming constant speed of spreading along the trabeculae. The results were compared with experimentally obtained epicardial activation maps generated by optical mapping with a voltage-sensitive dye. Simulated impulse propagation starting from the top of interventricular septum revealed the first epicardial breakthrough at the interventricular grove, similar to experimentally obtained activation maps. Likewise, ectopic activation from the left ventricular base perpendicular to dominant trabecular orientation resulted in isotropic and slower impulse spreading on the ventricular surface in both simulated and experimental conditions. We conclude that in the embryonic pre-septation heart, the geometry of the A-V connections and trabecular network is sufficient to explain impulse propagation and ventricular activation patterns.
Permanent Link: http://hdl.handle.net/11104/0295649