Distinct Biaxial Mechanical Properties between Right and Left Ventricles in Healthy Adult Sheep

Abstract

Right ventricle failure (RVF) is a serious disease with a 40% mortality rate where the right heart is unable to sufficiently pump blood to the body. RVF is associated with biomechanical changes such as extracellular matrix deposition and right ventricle (RV) wall stiffening. It has been well established that the RV is distinct from the left ventricle (LV) in embryologic origin, anatomy and function, and the two chambers' pathologies are significantly different. However, unlike left ventricle failure (LVF), the mechanisms of RVF are not well understood and it is partly due to the lack of knowledge in the difference in biomechanical properties and mechanobiology between the two chambers.To investigate the mechanical properties of the LV and RV, ex vivo biaxial tensile mechanical tests were performed in adult, healthy sheep hearts. Using homogenous, square slices of fresh ovine ventricles, 1:1 biaxial tests were performed and the stress‐strain responses were recorded. The elastic modulus at high and low strain regions were then derived as E1 and E2, respectively. The LV and RV showed distinct anisotropic mechanical properties: the longitudinal elastic moduli are larger than those of circumferential axis in the RV, while the opposite trend was observed in the LV. Moreover, we found that the RV was stiffer than the LV in the longitudinal direction (which is parallel to the outflow tract direction), whereas in the circumferential direction the RV was more compliant than the LV (Figure and Table). To our knowledge this is the first characterization and comparison of biaxial mechanical properties of LV and RV in a large animal model. Future work will test more heart samples and examine the histology to correlate structure to mechanical function. Overall, our finding that the healthy RV was stiffer than the healthy LV in the outflow tract direction may shed light on the biomechanical changes under pathological conditions, such as pressure overload induced RVF.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.