Bradycardia defined as heart rate (HR) < beats per minute (bpm) Atrial fibrillation with a ventricular rate > beats per minute (bpm) on echocardiograph (ECG) at rest Baseline QTc interval > milliseconds (ms), baseline resting bradycardia < beats per minute (bpm), or baseline resting tachycardia > bpm Active cardiac arrhythmias with rapid ventricular response (defined as heart rate greater than beats/minute) Unacceptable cardiac risk factors defined by any of the following criteria: patients with congenital long QT syndrome, any history of ventricular fibrillation or torsade de pointes, bradycardia defined as heart rate (HR) < beats per minute (bpm), left ventricular ejection fraction < % Have a resting heart rate of > beats per minute (bpm). Resting heart rate ? bpm History or presence of sustained bradycardia (less than or equal to beats per minute [BPM]) or history of symptomatic bradycardia, left bundle branch block, cardiac pacemaker or significant atrial tachyarrhythmias, as defined by the need for treatment Baseline Fridericia's corrected QT (QTcF) interval of > ms, participants with baseline resting bradycardia < beats per minute, or baseline resting tachycardia > beats per minute Patients with severe bradycardia (heart rate < beats per minute [bpm], hypotension, light-headedness, syncope) Persistent heart rate (HR) < or > beats per minute (bpm) Bradycardia defined as heart rate < beats per minute; patients with a pacemaker and heart rate >= beats per minute are eligible Persistent heart rate (HR) < or > beats per minute (bpm) Bradycardia as indicated by a heart rate of < beats per minute on the screening electrocardiogram (ECG) and on physical examination Resting bradycardia less than beats/min Subjects who have a heart rate >= beats per minute (bpm) or =< bpm determined by the ECG recorders algorithm on the screening ECG Resting heart rate - bpm Increased corrected QT (QTc) interval (QTc > ms), patients with baseline resting bradycardia < beats per minute (bpm), or baseline resting tachycardia > bpm Have QTc > ms or heart rate ? bpm or ? bpm at screening Presence of poorly controlled atrial fibrillation (ventricular heart rate > beats per minute [bpm]) Bradycardia (in the presence of known cardiovascular disease) as indicated by a heart rate of < beats per minute on the Screening electrocardiogram (ECG) recording. Heart rate < bpm during screening. Heart rate - beats per minute Heart rate > beats per minute (bpm) Patients with severe bradycardia (heart rate < beats per minute [bpm], hypotension, light-headedness, syncope) Pulse >= beat per minute (bpm) Bradycardia defined as heart rate (HR) < beats per minute (bpm); patients with pacemakers are eligible if HR >= bpm Clinically significant resting brachycardia (< beats per minute) Bradycardia defined as heart rate (HR) < beats per minute (bpm); patients with pacemakers are eligible if HR >= bpm Atrial fibrillation with a controlled ventricular rate (uncontrolled [i.e., > bpm] ventricular rate is not allowed [determined by an average of three beats in Lead II or representative beats if Lead II is not representative of the overall ECG]) Resting bradycardia < beats/min Bradycardia as indicated by a heart rate of < beats per minute on the screening electrocardiogram (ECG) and on physical examination; Patients with symptomatic bradycardia (heart rate < beats per minute [bpm], hypotension, light-headedness, syncope) Resting heart rate less than bpm at time of screening Bradycardia defined as heart rate (HR) < beats per minute (bpm); patients with pacemakers are eligible if HR >= bpm Bradycardia defined as HR< bpm. Patients with pacemakers are eligible if HR ? bpm. Resting bradycardia < beats/min Rhythm abnormalities (other than sinus bradycardia with HR < bpm) Patients with a cardiac pacer whose heart rate is set at a fixed rate and patients on concomitant medication that may limit increase in heart rate in response to hypotension Baseline QTc > ms or baseline symptomatic bradycardia < beats per minute Hypotension (systolic blood pressure < mmHg or bradycardia with a heart rate of < beats per minute on the ECG., unless pharmaceutically induced and thus reversible (i.e. beta blockers). Heart rate > beats per minute. Heart rate < beats per minute; Normal sinus rhythm with resting heart rate >= bpm on screening electrocardiogram (EKG) Exhibit American College of Sports Medicine contraindications to exercise which include a resting heart rate of > beats per minute (bpm), blood pressure > / mmHg or unstable angina Baseline tachycardia, heart rate (HR) > Uncontrolled tachy or bradyarrhythmia or active myocardial ischemia defined as either: atrial fibrillation with rapid ventricular response (heart rate [HR] > beats per minute [bpm]), ventricular tachycardia or nonsustained ventricular tachycardia, supraventricular tachycardia, third degree heart block, any heart rate less than bpm Resting heart rate > at the time of study enrollment Bradycardia: heart rate < beats per minute (BPM) Heart rate >= beats per minute Bradycardia of less than beats per minute, unless the subject has a pacemaker; Resting heart rate > at the time of study enrollment Resting heart rate > at the time of study enrollment Pulse ? beats/minute Bradycardia: heart rate < beats per minute (BPM) Bradycardia defined as HR. < bpm Uncontrolled sinus tachycardia (> beats per minute) Heart rate greater than or equal to - beats per minute (bpm), or below bpm (one re-screen allowed) Heart rate >