The purpose of this study is to determine if eplerenone is effective in the treatment of mild to moderate heart failure

Inclusion Criteria:

• Current symptoms consistent with mild to moderate heart failure (NYHA functional class II and III)
• LVEF (left ventricular ejection fraction) of <35% by equilibrium-gated RVG at screening
• Therapy with an angiotensin converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) and beta-blocker (BB) (unless documented intolerance) for at least 3 months duration and at dose that has not been adjusted within the previous 4 weeks

Exclusion Criteria:

• Current decompensated heart failure or heart failure hospitalization or severe heart failure (NYHA functional class IV) within 6 months of screening
• Use of eplerenone or spironolactone within 30 days of randomization or for more than 7 days within the previous 6 months