Pressure overload due to aortic stenosis leads to subclinical left ventricular (LV) dysfunction and global longitudinal strain (GLS) impairment even if ejection fraction is preserved. However, little is known about LV mechanics in aortic prosthetic valve (APV) stenosis. The study aimed to determine the role of myocardial strain and rotation in predicting prosthetic valve stenosis in mechanical APV patients. 60 patients with mechanical APV and 30 healthy individuals were evaluated. APV patients were analyzed in two groups; aortic valve mean gradient < 20 mmHg (27 normal gradient patients) and ≥ 20 mmHg (33 high gradient patients). Strain, rotation, and twist values were assessed using the speckle tracking method, and brain natriuretic peptide (BNP) levels were measured. Four-chamber (p < 0.001) and two-chamber (p = 0.008) longitudinal strain (LS) were higher in the control group. GLS was lower in the high gradient group than control and normal gradient groups (p < 0.001, p = 0.022). LS of lateral wall’s basal and mid segments were lower in normal and high gradient groups than the control group (p = 0.003, p = 0.008). While basal rotation was lower in the high gradient group than the control group (p = 0.048), there was no difference between the groups in terms of apical rotation, and twist. BNP levels were significantly different between the groups (p = 0.048). No correlation was found between aortic valve mean gradient and GLS, basal rotation, and BNP. In conclusions, LV GLS and basal rotation are depressed in high APV gradient patients; however, these parameters are not independent predictors of gradient increment.