The study will evaluate the efficacy and safety of both aliskiren monotherapy and aliskiren/enalapril combination therapy as compared to enalapril monotherapy, on morbidity and mortality in patients with chronic heart failure (NYHA Class II - IV.

• Drug: Enalapril monotherapy
  Enalapril monotherapy -10 mg
• Drug: Aliskiren monotherapy
  Aliskiren monotherapy-150 mg titrated to 300 mg
• Drug: Aliskiren / Enalapril combination therapy
  Aliskiren / Enalapril combination therapy- 150 mg/10 mg titrated to 300 mg/ 10 mg

• 1: Active Comparator
  Enalapril monotherapy -10 mg
  Intervention: Drug: Enalapril monotherapy
• 2: Experimental
  Aliskiren monotherapy
  Intervention: Drug: Aliskiren monotherapy
• 3: Experimental
  Aliskiren / Enalapril combination therapy-150 mg/10 mg titrated to 300 mg/ 10 mg
  Intervention: Drug: Aliskiren / Enalapril combination therapy

Inclusion Criteria:

• Patients with a diagnosis of chronic heart failure (NYHA Class II - IV):

  • LVEF ≤ 35% at visit 1. (local measurement, measured within the past 6 months assessed by echocardiogram, MUGA, CT scan, MRI or ventricular angiography)
  • Elevated BNP at visit 1: BNP ≥ 150 pg/ml (according to local measurement).
  • BNP ≥ 100 pg/ml (according to local measurement) and unplanned hospitalization with HF within the last 12 months prior visit 1.
• Patients must be treated with an ACE inhibitor at a stable dose (enalapril 10 mg daily at least or any other ACE inhibitor, e.g. ramipril, quinapril, lisinopril, fosinopril, perindopril, trandolapril; based on equivalent doses as described in the dose equivalence guidance table of ACEi's) for at least 4 weeks prior to visit 1

Exclusion Criteria:

• History of hypersensitivity to any of the study drugs including history or allergy to ACEi's as well as known or suspected contraindications to the study drugs or previous history of intolerance to high doses of ACEi's during up titration process.
• Patients treated concomitantly with both ARB and aldosterone antagonist in addition to study drug at visit 1.
• Current acute decompensated HF.
• Symptomatic hypotension and/or less than 95 mmHg SBP at visit 1 and/or less than 90 mmHg at visit 4.
• Renal disease likely to be life threatening or eGFR < 40 ml/min/1.73m2 as measured by the MDRD formula at visit 1 and eGFR < 35 ml/min/1.73m2 as measured by the MDRD formula at visit 4 or decrease of eGFR of more than 25% from visit 1 to visit 4 (according to local laboratory measurement).
• Serum potassium ≥ 5.0 mmol/L at visit 1 or ≥ 5.2 mmol/L at visit 4 (according to local laboratory measurement).
• Acute coronary syndrome, stroke, transient ischemic attack, cardiac, carotid or major vascular surgery, percutaneous coronary intervention (PCI) or carotid angioplasty, within the past 3 months prior to visit 1.
• Coronary or carotid artery disease likely to require surgical or percutaneous intervention within the 6 months after visit 1.
• Right heart failure due to severe pulmonary disease
• Other protocol-defined inclusion/exclusion criteria may apply