Growing evidence suggests that there may be a strong pathophysiologic link between congestive heart failure (CHF) and nocturnal breathing disorders due to nocturnal oxygen desaturation, intrathoracic pressure swings and sympathetic activation. It seems that sleep apnea contributes to systolic and diastolic heart failure, reduced left and right ventricular function and arrhythmia (e.g. atrial fibrillation). Therefore treatment of sleep apnea might alleviate cardiac symptoms and improve cardiac function. Nevertheless, the exact role of long term treatment of sleep apnea in heart failure patients remains to be elucidated.