Patients with severe congestive heart failure show increased fluid body content which is often resistant to conventional diuretic therapy. Therefore, chronic heart failure patients have frequent access to the emergency room and hospital for hemodynamic instability. Ultrafiltration is a simple renal replacement therapy which reduces fluid overload. The purpose of this study is to determine whether periodic ultrafiltration sessions maintain patients in stable clinical condition and reduce hospitalisations as well as access to emergency heart failure treatment.