- Abnormal ECGs which are clinically significant such as QT prolongation - QTc > 480 msec, clinically significant cardiac enlargement or hypertrophy, new bundle branch block, or signs of active ischemia. Patients with evidence of prior infarction who are New York Heart Association (NYHA) functional class II, III, or IV are excluded, as are patients with marked arrhythmia such as Wolff Parkinson White pattern or complete atrioventricular (AV) dissociation.