Computational heart models with realistic description of cardiac geometry and muscle characteristics have progressed significantly over the years. Clinical studies show that global longitudinal strain is reduced in heart failure with preserved ejection fraction (HFpEF), which suggests the deterioration of global left ventricular contractility. But this interpretation is contravened by a preserved ejection fraction (EF) and change in left ventricular (LV) geometry which also can affect global strains. With a goal to understand and conform these findings, a validated computational framework was used to identify the factors responsible in affecting systolic function metrics and HFpEF features. This computational framework consists finite element left ventricular (LV) model coupled to a closed loop lumped parameter circulatory model. The LV characteristics of healthy persons and HFpEF patients was modeled using an idealized prolate ellipsoid. A numerical investigation was carried out to understand the effect of LV stiffness, contractility and wall thicknesses had on HFpEF patients. Simulations were carried out under different conditions. Initially, these parameters were varied individually and later, simultaneously to understand their isolated and combined effects. While only passive stiffness was increased, all of EF, peak circumferential and longitudinal strain decreased. Which suggests that only stiffness cannot explain HFpEF properties. When heart models with increased wall thickness was used both longitudinal and circumferential strain decreased. And the EF showed an increasing trend. On the other hand, decreasing contractility had little effect on peak longitudinal effect. Our study suggests that it is likely that hypertrophy with reduced LV contractility is found in HFpEF patients.