Load-Free State of the Left Ventricular Myocardium of the Human Heart Using Magnetic Resonance Images

The aim of this research is to characterize the zero-load shape of the left ventricle of the heart. The shape of the heart in the heart cycle is not at free-loading state. To compute stresses at the diastolic state of the heart a load-free geometry is needed. The heart tissue is not still stress-free at this load-free geometry. In fact, the residual stresses as in all body parts exist. The source of these stresses comes from growth and remodeling which are active in all living tissues. Even assuming the residual stresses to be negligible, the heart tissue at diastolic pressure is not stress-free. Using the shape of the heart at this state to find the maximum stresses at systolic pressure ends in erroneous results. Since the heart works between systolic and diastolic pressures therefore all imaging outputs give its shape between these states. Modeling the heart should accurately represent the real structure of the heart while avoiding unnecessary complexities. Since the pressure in the left ventricle is higher than the other parts of the heart and the more anomalies occur in the left ventricle, this research focuses on load-free state of the left ventricle. The initial geometry of the load-free state of the left ventricle with the corresponding fiber directions was computed. Loading the computed heart geometry with its maximum uniform pressure shows less than one percent error compared to real data.