Selection criteria: Patients at the age of or over 22 years with severe chronic heart failure (chronic HF), NYHA class III-IV or NYHA class II with at least one hospitalization for HF within the last 24 months, with Left Ventricular Ejection Fraction (LVEF) less or equal 45% by means of echocardiography, radionuclidventriculography or cardiac MRI and Sleep Disordered Breathing (SDB) (apnoea-hypopnoea-index (AHI > 15/h) with 50% central events and a central AHI ≥ 10/h, no change of medication and no hospitalization for more than 1 month before randomization and medical therapy according to the applicable guidelines (European Society of Cardiology (ESC) and American College of Cardiology/American Heart Association (ACC/AHA) respectively).