Influence Of Microgravity On Left Ventricular Sphericity: A Finite Element Model Of The Heart

There is concern regarding the effects of microgravity exposure on cardiac function and loss of ventricular mass in astronauts. By Laplace’s law, the geometry of the ventricle is important in determining segmental wall stress and can induce alterations in myocardial mass. If microgravity exposure results in a variation in the ventricular radius of curvature, then we might also expect some cardiac remodeling during extended spaceflights. This study analyzes the theoretical impact of microgravity on changes in the geometric conformation of a finite element mesh model (FEM) created from the 3-dimensional geometry of the human left ventricle (LV) and attributed with material properties consistent with myocardial tissue. The Geometric Aspect Ratios (GAR, length to width quotient) of the LV were calculated and compared during simulations of the upright anatomic diastolic position in Earth’s gravity and in microgravity. The theoretical application of microgravity to the FEM model of the heart resulted in a 3.65% lower GAR of the LV as compared to that calculated for Earth’s gravity. This finding suggests that microgravity exposure could potentially result in changes in ventricular sphericity and radius of curvature and thereby alter the segmental myocardial wall stress.