Heart failure refractory to conventional therapy is a major and increasing public health and financial problem.Refractory heart failure is associated with hypervolemia due to sodium and fluid retention and azotemia due to renal hypoperfusion.There is extreme renal salt and water retention and marked secondary hyperaldosteronism.In this state, the kidneys are relatively resistant to diuretic therapy, and the use of very high doses of oral or parenteral diuretics only worsens the renal hypoperfusion, making the patient more azotemic.