Background:Systemic sclerosis is an autoimmune disease characterised by endothelial dysfunction and fibrosis of the skin and internal organs. Cardiac involvement during systemic sclerosis can be primary or secondary to pulmonary arterial hypertension and renal pathology. Among the disorders in systemic sclerosis, prolongation of QTc time is also associated with more anti-RNA polymerase III antibodies, longer duration, and severity of disease.Methods:This case-control study was performed on 35 patients with systemic scleroderma who filled in the American Society of Rheumatism (ACR / EULAR criteria) and 35 healthy subjects prior to entering the study. Then, the QTc distance was extracted from the electrocardiogram and calculated using the formula. The measured QTc distance in the electrocardiogram, QTc> 440ms in men and QTc> 460ms in women, was defined as QTc long. The patients and the control group then underwent echocardiography, and changes in QTc interval and their relations with echocardiographic findings were evaluated.Results:The results of this study indicated a significant relationship between QTc distance in patients with scleroderma compared with healthy controls. There was also a significant relationship between QTc and Skin Score of patients. However, there was no significant correlation between QTc distance and age, duration of disease, Anti-Centromere, Anti-Scl70, and pulmonary artery pressure.Conclusion:This study concludes that patients with scleroderma are at high risk for cardiac conduction impairment. The only factor that significantly correlated with QTc was the Skin Score of the patients.