- QTc prolongation defined as a QTc >450 ms for males or >470ms for females (Fridericia) for 3 consecutive ECGs; OR prior history of cardiovascular disease including heart failure that meets New York Hearth Association (NYHA) class III and IV definitions, OR history of myocardial infarction/active ischemic heart disease within one year of study entry; OR uncontrolled dysrhythmias; OR poorly controlled angina.