Relationship between the left ventricular size and the amount of trabeculations

Abstract

Contemporary imaging modalities offer non-invasive 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 modelled by scaling the ellipsoid whereupon the measurements of longitudinal strain, end-diastolic, end-systolic and stroke volume are derived and compared. When the trabeculated and non-trabeculated 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 0.35-0.41 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 non-trabeculated ventricle to produce the same stroke volume, which could be a possible explanation why athletes and pregnant women develop reversible signs of left ventricular non-compaction, 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 non-compaction.

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