Inclusion Criteria:
  1. Written informed consent must be obtained before any assessment was performed.
  2. Men and women ≥ 18 years of age.
  3. LVEF ≤ 40% subjects who were candidates for on-label sacubitril/valsartan treatment per standard of care.
  4. New York Heart Association (NYHA) Functional class II-IV.
  5. LVEF ≤ 40% via any local measurement within the past 6 months using echocardiography. If a subject was on a loop diuretic, they must be on a stable dose for 2 weeks prior to baseline.