- Myocardial infarction within 6 months prior to enrollment or New York Hospital Association Class III or IV heart failure, uncontrolled angina, severe uncontrolled ventricular arrhythmias, or electrocardiographic evidence of acute ischemia or significant conduction system abnormalities in the opinion of the investigator. Prior to study entry, any abnormality on electrocardiogram at screening must be determined and documented by the investigator as not medically relevant.