The Purpose of This Study is to Determine if Eplerenone is Effective in 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