15. Impaired cardiac function or clinically significant cardiac diseases, including any of the following: a.) History or presence of serious uncontrolled ventricular arrhythmias or presence of atrial fibrillation; b.) Clinically significant resting bradycardia (< 50 beats per minute); c.) Left ventricular ejection fraction (LVEF) assessed by 2-D echocardiogram (ECHO) < 50% or lower limit of normal (whichever is higher) or multiple gated acquisition scan (MUGA) < 45% or lower limit of normal (whichever is higher);