- History of any of the following cardiovascular events or conditions within the past 6 months prior to enrolment: myocardial infarction, unstable angina, cerebrovascular accident or transient ischemic attack, New York Heart Association Class ≥ II chronic heart failure, hypokalemia, significant arrhythmia*; QTc interval >430 msec or use of drugs that prolong the QT interval at screening; family history of long QT syndrome.(* Significant arrhythmias are defined as symptoms of syncope or severe palpitations (palpitations requiring referral to cardiac monitoring), or ECG findings of supraventricular tachycardia (including ventricular fibrillation) or ventricular ectopy (ventricular premature depolarization).