- Patients who have congestive heart failure (NHYA Class III or IV), unstable angina, sustained ventricular tachycardia, ventricular fibrillation, clinically significant bradycardia, advanced heart block or a history of acute myocardial infarction within the six months preceding enrollment. No new onset angina within 3 months preceding enrollment. No cardiac ventricular arrhythmia requiring antiarrhythmic therapy.