The Effect of Fluid Restriction in Congestive Heart Failure Complicated With Hyponatremia

Inclusion Criteria: * Age \> 18 years * Left Ventricular Ejection Fraction (LVEF) \< 40 At least two of the following signs of decompensated heart failure and fluid retention: * Weight gain \> 2 kg * Pulmonal Congestion * Jugular vein congestion * Peripheral oedemas * Hepatic congestion with ascites * Radiographic signs of fluid retention * Increased diuretic dose And * New York Heart Association (NYHA) class III-IV * Plasma sodium \< 135 mmol/L * Symptomatic heart failure and treatment with relevant heart failure medications (beta-blocker, diuretic, digoxin, angiotensin-converting-enzyme inhibitor, angiotensin-II receptor antagonist, spironolactone, hydralazine and/or nitrates)for at least 1 month * Hospitalization for decompensated heart failure within the last 48 hours * Given informed consent Exclusion Criteria: * Plasma sodium ≥ 135 mmol/L before randomization * Reduced kidney function (creatinine \> 200 μmol/L) * Severe hematologic disease * Hypovolemic hyponatremia (volume depletion or dehydration) * Intolerability to large or fast changes in fluid volume assessed by the investigator * Plasma sodium \< 120 mmol/L accompanied by neurologic symptoms * Anuria * Symptomatic systolic blood pressure (supine systolic blood pressure \< 90 mmHg) * Uncontrolled hypertension (systolic blood pressure \> 180 mmHg) * Uncontrolled diabetes diabetes mellitus * Adrenal insufficiency * Acute myocardial infarction, sustained ventricular tachycardia or ventricular fibrillation with…