5. Patients must not have active angina pectoris, or known heart disease of New York Heart Association Class III-IV. Patients must not have a history of myocardial infarction within 6 months prior to registration. No history or evidence of ventricular dysrhythmias or other unstable arrythmia is allowed (rate controlled atrial fibrillation is allowed if the patient is asymptomatic from a cardiac standpoint).