Genetically Targeted Therapy for the Prevention of Symptomatic Atrial Fibrillation in Patients With Heart Failure

Key Inclusion Criteria:

Must weigh at least 40 kg
Possess the β1389 Arg/Arg genotype
Left Ventricular Ejection Fraction (LVEF) < 0.50 assessed within 12 months prior to Screening
At least one episode of symptomatic paroxysmal or persistent AF within 180 days of Screening
Clinically appropriate for electrical cardioversion (ECV) if AF/AFL is present after study drug initiation
Receiving appropriate anticoagulation therapy prior to Randomization

Key Exclusion Criteria:

NYHA Class IV symptoms at the time of Randomization
Significant fluid overload at Randomization
Permanent AF at Screening
More than two previous ECV within 6 months of Randomization or if the most recent ECV failed to produce SR
Presence of an LVAD, or likely to requirement LVAD placement within 6 months of Randomization
History of a successful atrioventricular (AV) node ablation
History of an AF/AFL ablation within 30 days of Randomization
Evidence of an appropriate firing of an implanted cardioverter-defibrillator (ICD) device for ventricular tachycardia (VT) or ventricular fibrillation (VF) within 90 days of Randomization