This is a randomized, double-blind, placebo-controlled, multi-center, sequential cohort study in subjects with congestive heart failure (CHF) and impaired renal function who are on stable furosemide treatment (³ 40 mg daily). A total of 50 subjects will be randomized to each increasing dose level of SLV320 or placebo in a sequential fashion.

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.