AF is associated with severe CSA but not with moderate CSA in addition to age, use of digitalis, and left atrial size in patients with LV systolic dysfunction. Future studies evaluating the potential benefit of adaptive servo-ventilation therapy to prevent AF or to decrease the AF burden in heart failure patients should therefore focus on patients with severe central sleep apnea.

Obstructive sleep apnea and central sleep apnea with Cheyne-Stokes respiration are associated with an increased risk of cardiac arrhythmia. Apnea- associated arrhythmia may contribute to sudden cardiac death and premature mortality in those patients. Both forms of sleep apnea excert strong modulatory effects on the autonomic system with a special autonomic profile. Profound vagal activity is leading to bradyarrhythmias, and sypathico-excitation to tachyarrhythmias. Atrial fibrillation and ventricular arrhythmias in obstructive and central sleep apnea patients are mainly found in combination with cardiovascular comorbidity (coronary heart disease, hypertensive heart disease, chronic heart failure). Bradyarrhythmias in OSA are induced by a cardioinhibitory vagal reflex due to obstructed airway. CPAP-therapy has been demonstrated to reduce arrhythmias.

Sleep disordered breathing with predominant obstructive or central apnea is an under-recognized but highly prevalent comorbidity in patients with chronic heart failure. As the severity of heart failure increases the prevalence of central sleep apnea (CSA) and Cheyne-Stokes respiration (CSR) is also much more frequent. Cheyne-Stokes respiration is characterized by alternating periods of crescendo and decrescendo respiration followed by central apnea. Present data indicate that CSA-CSR is not only a compensatory response to severe heart failure but also a predictor of worse prognosis. However the results on long-term mortality are not consistent. The prognostic importance of night- and daytime CSR has to be further elucidated. Increased sympathetic nervous activity has been proposed to play a mayor role concerning progression and outcome of chronic heart failure by CSA-CSR.