Introduction: ECG abnormality is a major problem in COVID-19 patients, especially in theelderly, which can result in fatal dysrhythmias. In this article, QT interval prolongation was investigated in admitted Covid-19 patients of 20-50 years of age without any history of cardiac problems. Methods: This study is a descriptive and analytical study. All consenting patients admitted to the hospital for Covid-19 infectionaged 20-50 years old entered the study.Patients wit hunderlying heart and kidney disease, history of taking any medication or cardiac dysrhythmias were excluded. An electrocardiogram was performed on admission and the third dayof hospitalization. Results: Theaverage length of hospital stay was 7.9 ± 3.68 days, and all patients had QT interval prolongation after 3 days, but nocardiac dysrhythmia occurred. Therewas no statistically significant increase in QTc interval for each drug usedalone, but the use of various drugs that affect the electrical conduction of theheart and also the presence of underlying inflammation, especially in patient’sheart cells can be the underlying cause of QTc interval prolongation. Many Covid-19 patients have QT interval prolongation. It can be due the infectionitself, the drugs used for treatment or viral myocarditis. The results of thepresent study showed that taking drugs such as kaletra even for 3 days cansignificantly increase the QTc interval in patients, so care should be taken inthe use of these drugs to avoid iatrogenic cardiac disease in patients, althoughin most cases the increase was mild and didn’t cause mortality in patients.