Abstract Background The function of both ventricles have been suggested to be affected in patients with mitral stenosis. In this study, it was aimed to investigate deformation properties of right (RV) and left ventricles (LV) in mild and moderate rheumatic mitral stenosis (MS) patients with three-dimensional speckle tracking echocardiography (3D-STE). Methods A total of 60 patients were included in the study (20 patients with mild MS diagnosis, 20 patients with moderate MS diagnosis and 20 healthy volunteers). Three-dimensional echocardiography datasets were obtained for both ventricles in all patients. An example for RV assessment is shown in Figure 1. LV global longitudinal strain (GLS), LV torsion, RV free wall (FW) LS and interventricular septal (IVS) LS measurements were analyzed. Results The LV ejection fraction (EF), RV fractional area change and tricuspid annular plane systolic excursion values were statistically similar and in the normal range. The LV GLS measurements were significantly different among the groups by being highest in the control group and least in the moderate stenosis group (ANOVA,p < 0.001) (Table 1). Patients with MS showed higher torsional values, correlated with MS severity (ANOVA,p < 0.001) (Table 1). IVS LS, RVFW LS values obtained by RV analysis also differed significantly among groups. The FW-GLS values only showed significant difference between the control group and moderate MS group (Table 1). Conclusion Patients with mitral stenosis showed lower LV-GLS and higher LV torsion values. Although the LV GLS is affected; the LV EF was detected to be normal due to increase in LV torsion. RV deformation indices showed signıficant decrease in correlation with the severity of the mitral stenosis. In conclusion, our data suggest that subclinical LV and RV systolic dysfunction is present in mild-moderate MS patients and this dysfunction can be detected by 3D-STE. Table 1 Parameters Control group Mild MS Moderate MS P LV GLS (%) 23.3 ± 2.08 18.9 ± 1.3 17.5 ± 1.8 <0.001 LV torsion 1.5 ± 0.6 2.1 ± 0.6 2.6 ± 0.5 <0.001 IVS LS (%) 23 ± 3.0% 20 ± 2.6 17.1 ± 2.9 <0.001 RV FW LS (%) 25.4 ± 5 22.7 ± 3.2 21.1 ± 4.8 <0.001 FW; free-wall, GLS; global longitudinal strain, IVS; interventricular septum, LV; left ventricular, RV; right ventricular Abstract 1187 Figure 1