BACKGROUND: In patients with chronic heart failure (CHF), the presence of sleep-disordered breathing, including either obstructive sleep apnea or Cheyne-Stokes respiration-central sleep apnea, is associated with a poor prognosis. A large-scale clinical trial showed that continuous positive airway pressure (CPAP) did not improve the prognosis of such patients with CHF, probably because of insufficient sleep-disordered breathing suppression. Recently, it was reported that adaptive servo-ventilation (ASV) can effectively treat sleep-disordered breathing. However, there are no specific data about the efficacy of flow-triggered ASV for cardiac function in patients with CHF with sleep-disordered breathing. The aim of this study was to compare the efficacy of flow-triggered ASV to CPAP in patients with CHF with coexisting obstructive sleep apnea and Cheyne-Stokes respiration-central sleep apnea. METHODS AND RESULTS: Thirty-one patients with CHF, defined as left ventricular ejection fraction <50% and New York Heart Association class >or=II, with coexisting obstructive sleep apnea and Cheyne-Stokes respiration-central sleep apnea, were randomly assigned to either CPAP or flow-triggered ASV. The suppression of respiratory events, changes in cardiac function, and compliance with the devices during the 3-month study period were compared. Although both devices decreased respiratory events, ASV more effectively suppressed respiratory events (DeltaAHI [apnea-hypopnea index], -35.4+/-19.5 with ASV; -23.2+/-12.0 with CPAP, P<0.05). Compliance was significantly greater with ASV than with CPAP (5.2+/-0.9 versus 4.4+/-1.1 h/night, P<0.05). The improvements in quality-of-life and left ventricular ejection fraction were greater in the ASV group (DeltaLVEF [left ventricular ejection fraction], +9.1+/-4.7% versus +1.9+/-10.9%). CONCLUSIONS: These results suggest that patients with coexisting obstructive sleep apnea and Cheyne-Stokes respiration-central sleep apnea may receive greater benefit from treatment with ASV than with CPAP.