Study to Evaluate the Effect of SLV320 in Addition to Chronic Furosemide Treatment on Renal Function in Subjects With Congestive Heart Failure and Impaired Renal Function

Inclusion Criteria: * Male and female subjects aged 18 to85 years who gave written informed consent. * Subjects must have a history of chronic, symptomatic, New York Heart Association (NYHA) Class II-III CHF and impaired renal function (baseline eGFR of 20 to 75 mL/min/1.73m2). * Congestive heart failure should have been diagnosed at least 3 months before Visit 1 (Day 1) and the subjects should be on chronic treatment with furosemide (40 mg daily) for at least 3 weeks before Visit 1 (Day 1). * Subjects must be on stable doses of their individually optimized medication regimen for at least 4 weeks before Visit 1 (Day 1). Exclusion Criteria: * Any history of a convulsive disorder or pre-convulsive state and any risk for a convulsive disorder or pre-convulsive state (for example any past brain trauma, abuse of alcohol) will lead to an exclusion from the study. * Females of childbearing potential not using specified contraception, subjects with malignant tumors with a short life expectancy, subjects with known severe reactions to drugs and subjects with bilateral renal artery stenosis will be excluded from the study.