The QT interval of the electrocardiogram (ECG) represents the depolarization and repolarization of myocardial cells. Due to the QT interval variation with heart rate, multiple methods, often the Bazzett's formula has been applied to obtain a corrected measurement (QTc) [1]. Current evidence showed that the QTc interval prolongation prevalence is almost 30% in the intensive care unit [2,3]. Cardiac arrhythmias such as torsade de pointes and sudden cardiac death may occur when the QTc is prolonged either congenitally or by acquired causes [2].

The key cause of heart rate and rhythm disturbances are complex and often hard to ascertain [4]. QTc interval prolongation is caused by a combination of genetic and environmental factors. The particular risk factors of long QTc interval may differ from decades according to the fast pattern changes in the cardio-metabolic disorders and lifestyle habits [5].

Various drugs have been reported to prolong QTc interval, including psychotropic drugs, antimicrobial drugs, and cardiovascular drugs [6,7]. Moreover, numerous risk factors have been indicated to affect the QTc interval, such as age, sex, metabolic disease, genetic variants, and electrolyte abnormalities [8,9].

However, the risk factors of QTc interval prolongation in the general population of Iran have not been established in any recent study. Using a large general Iranian population, we evaluated the risk factors of prolonged QTc interval in both men and women, in order to fill in the gaps in the literature, as well as, providing evidence for possible QTc prolongation risk prediction in each gender.