Objectives: This study sought to evaluate left ventricular, right ventricular, and left atrial mechanics and their interactions in patients with congenital scoliosis without clinical heart failure. Methods: A total of 23 patients with a median age of 14 years and a median Cobb’s angle of 61° were studied. Ventricular and atrial myocardial deformation was measured using speckle tracking echocardiography. The results of the patients were compared with 22 controls. Results: Compared with controls, the patients had a significantly greater annular a velocity (p=0.04) and lower e/a ratio (p=0.03); the left ventricular deformation significantly decreased in radial global (p=0.04) and segmental systolic strain and early diastolic strain rate (p=0.03); the left atrial deformation showed a significantly lower positive strain (p=0.02), greater negative strain (p=0.01), and active contractile strain rate (p=0.01). For the patients, the Cobb’s angle was negatively correlated with the left ventricular global radial systolic strain (r=−0.65, p=0.001), left atrial positive strain (r=−0.68, p<0.001), and the left atrial negative strain was positively correlated with the left ventricular circumferential late diastolic strain rate (r=0.46, p=0.01). The left atrial conduit strain rate was positively correlated with the left ventricular circumferential early diastolic strain rate (r=0.42, p=0.03). The left atrial active contractile strain rate was positively correlated with the left ventricular longitudinal late diastolic strain rate (r=−0.4, p=0.03). Conclusions: Impaired left ventricular and altered left atrial mechanics occur relatively early in patients with congenital scoliosis, and are correlated with the severity of their scoliosis. Our findings provide evidence of preclinical heart dysfunction in patients with this disorder.