- History/evidence of any arrhythmia (for example, second- or third-degree heart block, atrial fibrillation, supraventricular tachycardia, symptomatic sinus bradycardia, junctional rhythm) or clinically significant cardiac disease or procedure (mitral valve regurgitation, heart murmur, angina/ischemia, congenital heart abnormalities, coronary artery bypass grafting surgery, or percutaneous transluminal coronary angioplasty). A history of additional risk factors for torsades de pointes (e.g., heart failure, hypokalemia, and family history of long QT syndrome).