Bradycardia defined as heart rate (HR) < 50 beats per minute (bpm) Atrial fibrillation with a ventricular rate > 100 beats per minute (bpm) on echocardiograph (ECG) at rest Baseline QTc interval > 470 milliseconds (ms), baseline resting bradycardia <45 beats per minute (bpm), or baseline resting tachycardia >100 bpm Active cardiac arrhythmias with rapid ventricular response (defined as heart rate greater than 100 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) < 50 beats per minute (bpm), left ventricular ejection fraction < 30% Have a resting heart rate of >100 beats per minute (bpm). Resting heart rate ? 50 bpm Patients with severe bradycardia (heart rate < 40 beats per minute [bpm], hypotension, light-headedness, syncope) Persistent heart rate (HR) < 50 or > 120 beats per minute (bpm) Bradycardia defined as heart rate < 50 beats per minute; patients with a pacemaker and heart rate >= 50 beats per minute are eligible Persistent heart rate (HR) < 50 or > 120 beats per minute (bpm) Bradycardia as indicated by a heart rate of < 45 beats per minute on the screening electrocardiogram (ECG) and on physical examination Subjects who have a heart rate >= 100 beats per minute (bpm) or =< 45 bpm determined by the ECG recorder’s algorithm on the screening ECG Resting heart rate 50-90 bpm Increased corrected QT (QTc) interval (QTc > 470 ms), patients with baseline resting bradycardia < 45 beats per minute (bpm), or baseline resting tachycardia > 100 bpm Have QTc >450 ms or heart rate ?100 bpm or ?45 bpm at screening Presence of poorly controlled atrial fibrillation (ventricular heart rate > 100 beats per minute [bpm]) Bradycardia (in the presence of known cardiovascular disease) as indicated by a heart rate of < 50 beats per minute on the Screening electrocardiogram (ECG) recording. Heart rate <50 bpm during screening. Heart rate 45-100 beats per minute Heart rate > 60 beats per minute (bpm) Patients with severe bradycardia (heart rate < 40 beats per minute [bpm], hypotension, light-headedness, syncope) Pulse >= 60 beat per minute (bpm) Bradycardia defined as heart rate (HR) < 50 beats per minute (bpm); patients with pacemakers are eligible if HR >= 50 bpm Bradycardia defined as heart rate (HR) < 50 beats per minute (bpm); patients with pacemakers are eligible if HR >= 50 bpm Atrial fibrillation with a controlled ventricular rate (uncontrolled [i.e., >110 bpm] ventricular rate is not allowed [determined by an average of three beats in Lead II or 3 representative beats if Lead II is not representative of the overall ECG]) Bradycardia as indicated by a heart rate of < 45 beats per minute on the screening electrocardiogram (ECG) and on physical examination; Patients with symptomatic bradycardia (heart rate < 50 beats per minute [bpm], hypotension, light-headedness, syncope) Resting heart rate less than 60 bpm at time of screening Bradycardia defined as heart rate (HR) < 50 beats per minute (bpm); patients with pacemakers are eligible if HR >= 50 bpm Bradycardia defined as HR< 50 bpm. Patients with pacemakers are eligible if HR ? 50 bpm. Rhythm abnormalities (other than sinus bradycardia with HR < 50 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 Hypotension (systolic blood pressure < 86 mmHg or bradycardia with a heart rate of <50 beats per minute on the ECG., unless pharmaceutically induced and thus reversible (i.e. beta blockers). Heart rate >100 beats per minute. Heart rate <50 beats per minute; Normal sinus rhythm with resting heart rate >= 80 bpm on screening electrocardiogram (EKG) Exhibit American College of Sports Medicine contraindications to exercise which include a resting heart rate of > 120 beats per minute (bpm), blood pressure > 180/100 mmHg or unstable angina Baseline tachycardia, heart rate (HR) > 100 Uncontrolled tachy or bradyarrhythmia or active myocardial ischemia defined as either: atrial fibrillation with rapid ventricular response (heart rate [HR] > 120 beats per minute [bpm]), ventricular tachycardia or nonsustained ventricular tachycardia, supraventricular tachycardia, third degree heart block, any heart rate less than 40 bpm Bradycardia: heart rate < 50 beats per minute (BPM) Heart rate >= 50 beats per minute Pulse ? 60 beats/minute Bradycardia: heart rate < 50 beats per minute (BPM) Bradycardia defined as HR. < 50 bpm Uncontrolled sinus tachycardia (> 120 beats per minute) Heart rate greater than or equal to -105 beats per minute (bpm), or below 45 bpm (one re-screen allowed) Heart rate > 100 Subjects with symptomatic bradycardia Participants with symptomatic bradycardia Medically significant (symptomatic) bradycardia Pathologic bradycardia or heart block Symptomatic bradycardia in the absence of a pacemaker. Current diagnosis of symptomatic bradycardia Medically significant (symptomatic) bradycardia. History or presence of sustained bradycardia (less than or equal to 60 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 > 470 ms, participants with baseline resting bradycardia < 45 beats per minute, or baseline resting tachycardia > 100 beats per minute History or presence of clinically significant ventricular arrhythmias, atrial fibrillation, resting bradycardia, or conduction abnormality History or presence of clinically significant ventricular arrhythmias, atrial fibrillation, resting bradycardia, or conduction abnormality Resting bradycardia less than 55 beats/min Clinically significant resting bradycardia Medically significant (symptomatic) bradycardia; Participants with baseline QTc greater than (>) 470 milliseconds or symptomatic bradycardia Clinically significant resting bradycardia Clinically significant resting brachycardia (< 50 beats per minute) Resting bradycardia < 55 beats/min Resting bradycardia < 55 beats/min Baseline QTc > 470 ms or baseline symptomatic bradycardia < 45 beats per minute Clinically significant resting bradycardia Clinically significant resting bradycardia Bradycardia of less than 50 beats per minute, unless the subject has a pacemaker; Clinically significant resting bradycardia