Relationship between the left ventricular size and the amount of trabeculations

Abstract

Contemporary imaging modalities offer noninvasive quantification of myocardial deformation; however, they make gross assumptions about internal structure of the cardiac walls. Our aim is to study the possible impact of the trabeculations on the stroke volume, strain, and capacity of differently sized ventricles. The cardiac left ventricle is represented by an ellipsoid and the trabeculations by a tissue occupying a fixed volume. The ventricular contraction is modeled by scaling the ellipsoid whereupon the measurements of longitudinal strain, end-diastolic, end-systolic, and stroke volumes are derived and compared. When the trabeculated and nontrabeculated ventricles, having the same geometry and deformation pattern, contain the same amount of blood and contract with the same strain, we observed an increased stroke volume in our model of the trabeculated ventricle. When these ventricles contain and eject the same amount of blood, we observed a reduced strain in the trabeculated case. We identified that a trade-off between the strain and the amount of trabeculations could be reached with a 0.35- to 0.41-cm dense trabeculated layer, without blood filled recesses (for a ventricle with end-diastolic volume of about 150 mL). A trabeculated ventricle can work at lower strains compared to a nontrabeculated ventricle to produce the same stroke volume, which could be a possible explanation why athletes and pregnant women develop reversible signs of left ventricular noncompaction, since the trabeculations could help generating extra cardiac output. This knowledge might help to assess heart failure patients with dilated cardiomyopathies who often show signs of noncompaction.

Ventricular mechanics in adolescent and adult patients with a Fontan circulation: Relation to geometry and wall stress

“…Reduced global systolic function might be caused by increased meridional wall stress in the more spherical ventricle. In our study, deformation in spherical ventricles was more load dependent compared to more ellipsoid‐shaped ones, indicating that the ellipsoid shape compensates for increasing afterload, while the spherical ventricles do not …”

Genomic analysis reveals a functional role for myocardial trabeculae in adults

“…Both studies lead to the discovery of the same loci, indicating that FD associations are independent of ventricular size. To replicate our findings we analysed the independent cohort of 1,129 people, applied the same image analysis pipeline and ran an equivalent genetic association study (10,673,171 genetic variants). As expected given the lower sample size, few of the associations passed a genome-wide threshold, however nearly all the estimates of effect direction were concordant (91% of comparisons concordant) between the two studies (correlation of beta estimates: r 2 = 0.516, Figure 13 in the Supplement).…”

“…8,9 However, the role of trabeculae in the ventricular mechanics of healthy adults and why such a critical compartment of the cardiovascular system retains a complex inner surface is unclear. Theoretical analyses have shown that an absence of trabeculae requires greater strain to maintain cardiac output, 10 and it has been proposed that their complex structure contributes to efficient intra-ventricular flow patterns. 11,12 Progress in understanding the functional role of organ components often relies on observing changes during physiological experiments or by identifying genes that selectively influence relevant morphology.…”

Left Ventricular Trabeculations in Athletes: Epiphenomenon or Phenotype of Disease?

“…Paun et al studied the effect of LV trabeculations on ventricular performance and size using computational modelling. They demonstrated that in a smooth, non-trabeculated LV, increases in stroke volume came at considerable energetic cost, requiring increasingly high longitudinal strain, whereas a trabeculated LV was capable of achieving high stroke volumes without incurring exponential elevations in strain [ 13 ]. Both of these studies, however, have important limitations in mathematical oversimplification of left ventricular geometry, viscoelastic properties of trabeculae and myocardial deformation.…”