Study Patients
Eligibility requirements at screening included an
age of at least 18 years, New York Heart Association
(NYHA) class II, III, or IV symptoms, and an ejection
fraction of 40% or less (which was changed
to 35% or less by an amendment to the protocol
on December 15, 2010). Patients were required to
have a plasma B-type natriuretic peptide (BNP)
level of at least 150 pg per milliliter (or an N-terminal
pro-BNP [NT-proBNP] level ≥600 pg per milliliter)
or, if they had been hospitalized for heart
failure within the previous 12 months, a BNP of
at least 100 pg per milliliter (or an NT-proBNP
≥400 pg per milliliter). Patients taking any dose
of an ACE inhibitor or ARB were considered for
participation, but for at least 4 weeks before screening,
patients were required to take a stable dose of
a beta-blocker and an ACE inhibitor (or ARB) equivalent
to at least 10 mg of enalapril daily.23
Exclusion criteria included symptomatic hypotension,
a systolic blood pressure of less than