Although the traditional determinant of renal dysfunction in heart failure was suggested as decreased cardiac output and renal hypo perfusion, recent studies have demonstrated the association of persistent systemic venous congestion and kidney dysfunction. Relief of the congestion has demonstrated to improve renal functions in decompensated heart failure. The current trial was set up to investigate the changes of renal venous impedance and renal arteriolar resistivity indices with diuretic therapy, in patients with congestive renal failure. The investigators asked whether measurement of renal venous impedance index or renal arteriolar resistivity index can guide the practice of diuretic therapy.

Inclusion Criteria:

• Decompensated heart failure
• Elevated serum creatinine levels on admission

Exclusion Criteria:

• Atrial fibrillation
• Obstructive uropathy
• Patients with ascites
• Patients who exposed the potential nephrotoxic drugs in the previous week (metformin, antibiotics, chemotherapeutics, iodinated contrast agents and non-steroidal anti-inflammatory agents)
• Patients who needed positive inotropic agents