Cardiac Trabeculae Parameters and Implications for Cardiovascular Health
Authors: Kern Jessica Ann , Habib Michael Bruce 
Published: June 2021

Quantitative data describing the cardiac trabecular muscle architecture and its variation between individuals are practically absent in the technical literature. Consequently, the relationship of trabecular muscle variation to cardiovascular diseases is largely unknown. Modeling work, using simulations of simplified heart morphology, has previously demonstrated the likely importance of the trabecular layer for enhanced cardiac output, and secondary findings indicated that variation in trabecular mass, diameter, and orientation are impactful on heart functioning. Measurements of variation in trabecular muscle are therefore of potential interest in both a clinical and basic science context. Using a large cadaveric sample, we have quantified the variability in trabecular mass in the left ventricle and investigated its correlation with one known factor in cardiovascular health ‐ relative heart size.

With permission from the Keck School of Medicine at the University of Southern California and the USC Anatomical Gift Program, 74 human cadavers managed by the Integrative Anatomical Sciences Department were utilized in the study. The donor population all had known cause of death and a brief summary of pathologies. A standardized region of trabeculae was examined on the posterior‐medial wall of the left chamber where the interventricular septum and posterior papillary muscle meet the apex of the heart.

Images were taken of the standardized area and analyzed using ImageJ. Thresholding was used to calculate trabecular density as a ratio of trabeculated area to total area. Use of a fixed threshold, in combination with standardization of lighting, camera position, and region of interest, allowed us to produce a robust comparative metric. Relative trabecular area was the primary comparison of interest since the specific values are dependent on the thresholding value (which was chosen for methodology ease and was biologically arbitrary). Cardiothoracic ratios were also obtained for all individuals. The maximal horizontal thoracic diameter was standardized at rib seven, and the cardiac diameter was taken at the longest basal diameter of the heart using digital calipers.

The fraction of trabeculation varied from 64.50–82.12%, demonstrating that trabecular muscle density is highly variable between individuals. Qualitatively, there was also large variations in diameter, layering, and average orientation of trabecular muscle. We found that there is a relatively strong correlation (Pearson Product Moment Coefficient of 0.43, p<0.08) between relative trabecular area and cardiothoracic ratio. Based on these results, it is plausible that variations in cardiac trabeculae have an impact on overall heart health and long‐term risk for cardiovascular disease. Trabecular muscle variation could be a useful correlate in understanding individual variation in cardiac efficiency, development, and disease. Our work provides a framework for future analysis of this understudied aspect of human variation. Future work on this problem should include trabecular orientation and diameter as additional variables. Digital imaging to source data may also provide a more complete picture of trabecular morphology and predictors of cardiac efficiency.

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This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.