- Unstable/underlying cardiovascular disease defined as: a. Congestive heart failure (NYHA class III-IV), stroke, transient ischemic attack, unstable angina pectoris, or myocardial infarction within the 6 months prior to screening (V1) b. Mean triplicate 12-lead ECG demonstrating a QT interval (corrected using Fridericia's formula (QTcF)) >450 msec in males and >470 msec in females at Screening, (V1) or a history or evidence of long QT syndrome. c. Sustained heart rate >100 beats per minute (BPM) (at rest) at screening (V1), prior to randomization (V3 Day -1), or prior to dosing (V3 Day 0). d. Any episode of atrial fibrillation, ventricular tachycardia (defined as ten (10) or more beats with heart rate greater than 130 beats per minute), ventricular fibrillation, firing of an implantable cardiac defibrillator (ICD) for documented ventricular ectopy, or other clinically significant documented arrhythmias within 3 months prior to administration of study drug (V3 Day 0).