Exclusion Criteria:
  1. Pregnant or nursing women.
  2. History of hypersensitivity to any of the study drugs.
  3. History of angioedema drug related or otherwise.
  4. Subjects with a heart transplant or ventricular assistance device (VAD) or intent to transplant (on transplant list) or implant a VAD.
  5. Subjects with a cardio resynchronization therapy device (CRT/CRT-D) implanted within 6 months of screening visit.
  6. Subjects who were currently taking inotropic agents.
  7. Bile acid sequestering agents such as cholestyramine or colestipol were prohibited to avoid interference with study drug absorption.
  8. Any hospital admission/discharge related to heart failure within 2 weeks prior to baseline.
  9. The use of outpatient or inpatient i.v. diuretic therapy within 2 weeks prior to baseline.
  10. Potassium > 5.2 mEq/L at screening.