Pulmonary arterial hypertension (PAH) is a fatal and rapidly progressive disease, and right ventricular failure is the main cause of death in patients with PAH. This study aims to determine the mechanical cues that can trigger the growth and remodelling of the heart. To this end, two bi-ventricular models of a control rat heart and a diseased rat heart with PAH are reconstructed, respectively, and then the growth amount is estimated by warping the PAH heart to the control heart. Finally, correlation analysis between mechanical cues (stress and strain) and growth tensors demonstrates principal strain may be a triggering cue for myocardial growth under PAH