DECIDE-HF: Heart Rate Variability in Heart Failure Patients

Inclusion Criteria: * Subject has signed and dated the study-specific informed consent form * Subject is 18 years of age or older * Subject is expected to remain available for follow-ups * Subject is able and willing to comply with the protocol requirements * Subject has predominant Normal Sinus Rhythm * Subject has systolic Heart Failure and is at the moment of enrollment in NYHA class II or III and has an ejection fraction of less then 40% * Subject has had a HF-related hospitalization in the past 12 months Exclusion Criteria: * Subject needs permanent atrial pacing (\> 10%) * Subject has intermittent 2nd or intermittent 3rd degree block * Subject has persistent or permanent AF * Subject has Long QT syndrome, Brugada syndrome, Jervell and Lange- Nielsen syndrome, Romano-Ward syndrome, Andersen-Tawil syndrome or Timothy's syndrome * Subject has had recent (\<2 months) acute coronary syndrome * Subject has had recent (\<2 months) revascularization * Subject has a pending cardiac transplant or revascularization * Subject has severe stenotic valvular heart disease * Subject has severe pulmonary (forced expiratory volume in 1 s \< 1 L) hepatic or renal (plasma creatinine \> 0.2 mmol/L) disease * Subject is participating in another study that may affect the results of this study