Patients with decompensated heart failure have high rates of mortality and morbidity despite recent improvements in diagnosis and treatment. Some aspects of their presentation such as renal failure, hyponatremia and congestive phenomena have received special attention, as they are associated with worse prognosis. The infusion of hypertonic saline solution has been tested in different conditions of cardiovascular collapse. Current evidence indicates that the infusion of hypertonic solution in heart failure patients can provide clinical and haemodynamic improvement. The investigators are testing the hypothesis that the infusion of hypertonic solution in association with diuretics may prevent the occurrence of renal dysfunction in patients with decompensated heart failure.

Inclusion Criteria:

• Age over 18 years old
• Heart failure according to Framingham criteria
• Episode of acute decompensation,with need of in-hospital treatment
• Presence of congestive phenomena

Exclusion Criteria:

• Patient denial
• Left-ventricle ejection fraction over 0,4, as measure by transthoracic echocardiography
• Rheumatic disease
• Restrictive cardiomyopathy
• Alcohol abuse
• Chronic obstructive pulmonary disease
• Cancer
• Pulmonary embolism during the last 6 months
• Surgical procedures or acute illness during the last 30 days
• Chronic or acute infection
• Any other circumstance that may hamper patient prognosis for the next 6 months
• Serum creatine over 3.0mg/dL
• Serum potassium over 5.5 mEqs/L
• Any specific condition associated to the acute episode of decompensation, such as new onset cardiac arrhythmias, heart ischemia, infection, etc.