Background: Adaptive servo-ventilation (ASV) has been used as therapy for heart failure (HF). The objective of the present study was to estimate the effect of ASV on 1-year prognosis in HF patients. Methods and Results: After optimizing medical therapy, a 1-year follow-up study was conducted of 85 HF patients (mean age, 72±10 years; 46 men), categorized as New York Heart Association class II-IV. The patients were classified into 2 groups based on adherence to ASV therapy. Use of ASV for ≥4h/night was designated as good adherence, and use of ASV for <4h/night was designated as poor adherence. The incidence of fatal cardiovascular events including death from progression of HF, cardioembolic stroke, and fatal cardiac arrhythmias was tracked. Fifty-seven patients were classified into the good adherence group. After 1-year follow-up, the survival rate calculated using Kaplan-Meier analysis was significantly higher in the good adherence group than in the poor adherence group (P=0.0046, log-rank test). In a Cox proportional hazards model, the odds ratio (95% confidence interval) of fatal cardiovascular events was 0.53 (0.27-0.99) for the good ASV adherence group (P=0.046). Conclusions: ASV prevents fatal cardiovascular events and improves survival in HF patients. (Circ J 2012; 76: 661-667)