Background. Children with congenital heart diseases (CHDs) may have a risk of developing myocardial injury caused by volume and pressure overload. Objective. To evaluate the incidence of myocardial injury in children with cyanotic and acyanotic CHDs using cTnI assay and to correlate it with different hemodynamic parameters. Methods. This study included 80 children with CHDs (40 acyanotic and 40 cyanotic) as well as 40 healthy children (control group). This evidence concerns the gene TNNI3 and congenital heart disease.