- Corrected QT (QTc) criteria： QTc <450 milliseconds (msec) or QTc <480msec for patients with bundle branch block. The QTc is the QT interval corrected for heart rate according to either Bazett's formula (QTcB), Fridericia's formula (QTcF), or machine or manual overread. For subject eligibility and withdrawal, QTcF will be used. For purpose of data analysis, QTcF will be used. The QTc should be based on single or averaged QTc values of triplicate electrocardiograms (ECGs) obtained over a brief recording period.