History or presence of sustained ventricular tachyarrhythmia. (Patients with a history of atrial arrhythmia are eligible but should be discussed with Novartis prior to enrollment) Any history of ventricular fibrillation or torsade de pointes Bradycardia defined as HR< 50 bpm. Patients with pacemakers are eligible if HR ≥ 50 bpm Screening ECG with a QTcF > 450 msec Right bundle branch block + left anterior hemiblock (bifascicular block) Patients with myocardial infarction or unstable angina ≤ 6 months prior to starting study drug Congestive heart failure (CHF) that meets New York Heart Association (NYHA) Class II to IV definitions and/or ejection fraction <50% by MUGA scan or by transthoracic echocardiogram Other clinically significant heart disease (e.g. uncontrolled hypertension, or history of labile hypertension)