Computational Parametric Studies Investigating the Global Hemodynamic Effects of Applied Apical Torsion for Cardiac Assist

Healthy hearts have an inherent twisting motion that is caused by large changes in muscle fiber orientation across the myocardial wall and is believed to help lower wall stress and increase cardiac output. It was demonstrated that applied apical torsion (AAT) of the heart could potentially treat congestive heart failure (CHF) by improving hemodynamic function. We report the results of parametric computational experiments where the effects of using a torsional ventricular assist device (tVAD) to treat CHF were examined using a patient-specific bi-ventricular computational model. We examined the effects on global hemodynamics as the device coverage area (CA) and applied rotation angle (ARA) were varied to determine ideal tVAD design parameters. When compared to a baseline, pretreatment CHF model, increases in ARA resulted in moderate to substantial increases in ejection fraction (EF), peak systolic pressures (PSP) and stroke work (SW) with concomitant decreases in end-systolic volumes (ESV). Increases in device CA resulted in increased hemodynamic function. The simulation representing the most aggressive level of cardiac assist yielded significant increases in left ventricular EF and SW, 49 and 72% respectively. Results with this more realistic computational model reinforce previous studies that have demonstrated the potential of AAT for cardiac assist.