Although half of the patients with HF has normal ejection fraction or slightly altered (HF-PEF) and the prognosis differs little from those with reduced ejection fraction, the pathophysiology of HF-PEF is still poorly understood.

Sodium restriction is the most common measure of self-care oriented to HF patients for management of congestive episodes. The role of this orientation in the treatment of patients with preserved ejection fraction, however, is still unclear. The evaluation of the effects of sodium restriction on neurohormonal activation and episodes of decompensation in HF-PEF can promote a better understanding of the pathophysiological progression of this complex syndrome.

This is a randomized, parallel trial with blinded outcome assessment. The sample will include adult patients (aged ≥18 years) with a diagnosis of HF-PEF admitted for HF decompensation. The patients will be randomized to receive a diet with sodium and fluid intake restricted to 0.8 g/day and 800 mL/day respectively (intervention group) or an unrestricted diet, with 4 g/day sodium and unlimited fluid intake (control group), and followed for 7 days or until hospital discharge. The primary outcome shall consist of weight loss at 7 days or discharge. The secondary outcome includes assessment of clinical stability, neurohormonal activation, daily perception of thirst and readmission rate at 30 days.

Inclusion Criteria:

• Patients of both sexes
• Age equal to or above 18 years
• Diagnosis of heart failure whit preserved ejection fraction (LVEF> 50%)
• Patients hospitalized for heart failure decompensation whit hospital admission within 36 hours, who agree to participate in the study by signing the informed consent.

Exclusion Criteria:

• Patients who present values of endogenous creatinine clearance less than or equal to 30 ml / min;
• Cardiogenic shock,
• Those with survival compromised by another disease in evolution and / or difficulty adhering to treatment (dementia, cognitive impairment)