- History of unstable cardiac syndromes including unstable angina, coronary artery bypass graft, myocardial infarction or coronary stenting within 2 months of screening; NYHA Class 3-4 CHF; history of ventricular tachycardia, ventricular fibrillation, personal or family history of sudden death, Long QT Syndrome, or Torsade de Pointes; HR<50BPM; having taken any Class 1 or Class 3 antiarrhythmic medications or medicines known to prolong the QT interval or be associated with Torsade de Pointes.