Inclusion Criteria

• Compensated CHF without Renal Dysfunction
  • Left ventricular ejection fraction equal or less than 40% as assessed by echocardiography, nuclear scan, MRI, or left ventriculogram within the past 36 months
  • Stable New York Heart Association (NYHA) class II and III symptoms defined by
    • No change in NYHA symptoms over the past 3 months
    • On stable doses of an ACE inhibitor, beta blocker, digoxin, furosemide, or angiotensin II receptor type 1 blocker over the past 3 months
    • No episode of decompensated CHF over the past 6 months
  • Calculated creatinine clearance of equal or less than 80 ml/min, using the Cockcroft-Gault formula assessed within the past 36 months
    • Confirmatory calculated creatinine clearance equal or less than 80 ml/min at the time of enrollment
• Compensated CHF with Renal Dysfunction
  • Left ventricular ejection fraction of equal or less than 40 assessed by echocardiography, nuclear scan or left ventriculogram within the past 36 months
  • Stable New York Heart Association (NYHA) class II and III symptoms defined by
    • No change in NYHA symptoms over the past 3 months
    • On stable doses of an ACE inhibitor, beta blocker, digoxin, furosemide, or AT1 blocker over the past 3 months
    • No episode of decompensated CHF over the past 6 months
  • Calculated creatinine clearance of equal or less than 60 ml/min and greater than 20 ml/min, using the Cockcroft-Gault formula and assessed within the past 36 months
    • Confirmatory calculated creatinine clearance equal or less than 60 ml/min and greater than 20 ml/min at the time of enrollment

Exclusion Criteria

• Prior diagnosis of intrinsic renal disease including renal artery stenosis of > 50%
• Peritoneal or hemodialysis within 90 days 
• Anticipation that dialysis or ultrafiltration of any form will be required during the study period
• Taking aldosterone antagonist
• Hospitalization for decompensated CHF during the past 6 months
• On other diuretics besides furosemide
• Myocardial infarction within 6 months of screening
• Unstable angina within 6 months of screening or any evidence of myocardial ischemia
• Significant valvular stenosis
• Hypertrophic, restrictive or obstructive cardiomyopathy
• Constrictive pericarditis
• Primary pulmonary hypertension
• Biopsy proven active myocarditis
• Severe congenital heart diseases
• Sustained ventricular tachycardia or ventricular fibrillation within 14 days of screening
• Second or third degree heart block without a permanent cardiac pacemaker
• Stroke within 3 months of screening or other evidence of significantly compromised central nervous system (CNS) perfusion
• Alanine Aminotransferase (ALT) result >1.5 times the upper limit of normal
• Serum sodium of < 125 milliequivalent (mEq)/dL or > 150 mEq/dL
• Serum potassium of < 3.5 mEq/dL or > 5.5 mEq/dL
• Serum digoxin level of > 2.0 ng/ml
• Hemoglobin < 10 gm/dl
• Other acute or chronic medical condition or laboratory abnormality which may increase the risks associated with study participation, or may interfere with interpretation of the data
• Received an investigational drug within 1 month prior to dosing
• Has an allergy to iodine
• Pregnant or breastfeeding
• In the opinion of the investigator is unlikely to comply with the study protocol, or is unsuitable for any reason