13-18 Vincenzo Patruno.qxd:-

Sleep breathing disorders (SBD) are commonly divided in three syndromes: obstructive sleep apnea syndrome (OSA), central sleep apnea-hypopnea syndrome (CSA) and Cheyne-Stokes breathing syndrome (CSR), the latter two both characterized by cyclic non-obstructive breathing patterns. Because the prevalence of CSA-CSR in chronic heart failure (CHF) population has been reported from 40% to 60%, CSA-CSR is the more frequent respiratory consequence of such cardiovascular illness. CSACSR has been associated with increased mortality in heart failure patients, but a causal role for CSA-CSR in the morbidity and mortality of heart failure awaits more definitive evidence. In fact, it is not yet known whether CSA-CSR is an epiphenomenon in the setting of heart failure or whether it may itself lead to increased risk or progression of heart failure. CPAP is the most studied form of treatment for CSACSR. However, in randomized trials of long term duration, several forms of non-invasive positive airway pressure, including CPAP, bi-level, adaptive pressure support ventilation and nocturnal oxygen therapy, have been shown to alleviate CSA-CSR in heart failure patients. Nevertheless, at present, none therapeutic approach was ideal with respect to both efficacy and tolerance, nor has any available therapy been demonstrated to improve survival. In CHF patients with CSA-CSR, standard employment of CPAP cannot be recommended at present, though the post hoc analysis of the CANPAP study is intriguing and suggests that CPAP responders may benefit prognostically. Furthermore, the results of the CANPAP study should not be extrapolated to heart failure patients with OSA, which is much more effectively suppressed by CPAP. Finally, there is a need to examine novel treatment options for CSA-CSR in patients with CHF, as these patients appear to have the worst prognosis and therefore the most to gain if successful treatment of CSA-CSR improves survival.