16. Concomitant medications known to prolong QT interval, or with factors that increase the risk of QTc prolongation or risk of arrhythmic events (such as heart failure, hypokalaemia, congenital long QT syndrome, family history of long QT syndrome), or unexplained sudden death under 40 years of age. Inability to discontinue medication with agents designated as having a risk of Torsades de Pointes due to QT prolongation (see Appendix 5)