Pulmonary hypertension (PH) is a rare disease where the pulmonary arteries become constricted. This disease is diagnosed clinically when the pulmonary arterial pressure is greater than 25 mmHg at rest (and greater than 30 mmHg during exercise). Without treatment, PH can lead to right heart failure, the most common cause of death in PH patients. The increase in pulmonary arterial pressure impacts the right ventricular (RV) mechanics. Unfortunately, it is not clear how PH affects the ventricular mechanics of pediatric patients. In this study, we seek to use the Hyperelastic Warping method to estimate the circumferential, longitudinal, and radial strains in the left ventricle (LV) and RV. The main goal of this research is to compare the PH patients' strain data to those of normal patients in order to detect abnormalities in the biventricular mechanics. Geometrical surfaces of the RV cavity, LV cavity, and epicardium surfaces were reconstructed from the magnetic resonance images (MRI). Based on the hyperelastic warping method that was implemented using the finite element method, the patient- specific biventricular models were deformed into alignment with the MRIs acquired in a cardiac cycle. Biventricular strains of the PH patients were then computed from the deformation. This study will help better understand PH and its effects on biventricular mechanics.