- Patients with unstable angina, congestive heart failure, or with a history of a myocardial infarction within 6 months; patients with high-risk uncontrolled arrhythmias (ventricular tachycardia, high-grade atrioventricular [AV] block, supraventricular arrhythmias which are not adequately rate-controlled); patients with uncontrolled hypertension (i.e., over 160/90 mmHg); patients who are controlled on anti-hypertensive medication will be allowed to enter the study