 3. Impaired cardiac function including any one of the following: Screening ECG with QTc 450 msec confirmed by central laboratory prior to enrollment in study; Pts with congenital long QT syndrome; History of sustained ventricular tachycardia; History of ventricular fibrillation or torsades de pointes; Pts with myocardial infarction or unstable angina within 6 mo. of study entry; Congestive heart failure; Right bundle branch block with left anterior hemiblock bifascicular block 