Fluid balance in heart failure.

Fluid retention is a major determinant of symptoms in patients with heart failure (HF), and it is closely associated with prognosis. Hence, congestion represents a critical therapeutic target in this clinical setting. The first therapeutic strategy in HF patients with fluid overload is optimization of diuretic intervention to maximize water and sodium excretion. When diuretic therapy fails to relieve congestion, renal replacement therapy represents the only alternative option for fluid removal, as well as a way to restore diuretic responsiveness. On this background, the pathophysiology of fluid balance in HF is complex, with heart, kidney, and lung being deeply involved in volume regulation and management. Therefore, the interplay between these organs should be appreciated and considered when fluid overload in HF patients is targeted.