At present the standard management of fluid overload in patients with congestive heart failure (CHF) involves limiting the intake of salt and water while administering high dose diuretics, often at the cost of deteriorating kidney function. However, another group of researchers has previously shown that intravenously infusing small volumes of concentrated saline during diuretic dosing and liberalizing dietary salt intake while continuing to limit water consumption resulted in improved fluid removal in CHF patients. Furthermore, less deterioration in kidney function, shorter hospitalizations, reduced readmission rates, and even reduced mortality were observed. The present study will examine this novel therapy in a population of 60 patients with underlying severe CHF and kidney dysfunction hospitalized for the management of fluid overload. Half of these patients will receive investigational treatment with concentrated salt infusions and liberalized salt consumption during diuretic therapy. All patients will otherwise receive the standard therapies for heart failure, including restrictions on water consumption. This study will attempt to verify the improvements in clinical endpoints previously described and define the mechanisms of enhanced fluid removal.

Inclusion Criteria:

• Adult patients (age ≥18) admitted with CHF exacerbation with NYHA Class III-IV symptoms at screening.
• Left ventricular ejection fraction </= 45%, as determined by previous echocardiogram, left ventricular angiogram, or thallium myocardial imaging.
• Estimated GFR <60 ml/min/1.7m² with significant prerenal physiology as judged by prior documented volume mediated changes in renal function, a fractional excretion of urea <35%, or a fractional excretion of sodium <1%. For GFR 30-60: must have serum sodium </= 135 mEq/L OR large home diuretic dose (total daily loop diuretic dose >/= 120 mg/d in furosemide equivalents OR concomitant thiazide use). For GFR <30: no additional criteria needed.

Exclusion Criteria:

• Admit estimated GFR < 15mL/min or predicted need for chronic hemodialysis within the next 60 days.
• Cause of acute kidney injury other than prerenal physiology.
• No loop diuretic prior to admission or loop diuretic initiated within the 2 wks prior to admission.
• Medicine or dietary noncompliance expected to prevent successful study participation.
• > 36hrs since presentation to screening.
• Serum Na > 145 mEq/L OR < 120 mEq/L at screening.
• Systolic blood pressure > 180 mmHg at screening.
• Presentation with acute coronary syndrome OR left heart catheterization planned at screening.
• Current or impending respiratory failure at screening.
• Current calcineurin inhibitor or nesiritide use.
• Nephrotic-range proteinuria.
• Clinical evidence for the presence of cirrhosis with bilirubin >/= 2mg/dL or international normalized ratio (not on coumadin) >/= 1.7.
• Presence of another active medical issue which may prolong hospital admission or delay aggressive CHF therapy.
• Participation in another interventional study.
• Pregnancy.
• Prisoners.