- Patients with clinically significant (cardiac) disorders: QTc interval prolongation (QTc ≥500ms), recent acute myocardial infarction, uncompensated heart failure (working diagnosis), acute coronary syndrome (ACS), arrhythmias treated with class IA and III antiarrhythmic medicinal products, history of ventricular arrhythmia, history of torsades, clinically significant bradycardia, second or third degree heart block, uncorrected hypokalaemia (potassium level 3.0 or lower);