Effects of nocturnal oxygen therapy in patients with chronic heart failure and central sleep apnea: CHF-HOT study

It was previously reported that nocturnal home oxygen therapy (HOT) significantly improved not only sleep disordered breathing (SDB), but also quality of life (QOL) and left ventricular ejection fraction (LVEF) in two trials. To strengthen the statistical reliability of the above efficacies of HOT and to assess the effects of 12-week nocturnal HOT on suppression of ventricular arrhythmias, we combined the two trials and undertook a post hoc analysis. Ninety-seven patients with chronic heart failure (CHF) and central sleep apnea were assigned to receive HOT (45 patients) or not (52 patients). HOT resulted in greater reduction in the apnea-hypopnea index (AHI) (-11.4 +/- 11.0 vs. -0.2 +/- 7.6 events/h, p < 0.01), which is associated with greater improvement in the Specific Activity Scale (0.8 +/- 1.2 vs. 0.0 +/- 0.6, p < 0.01), New York Heart Association (NYHA) functional class (p < 0.01), and LVEF (p = 0.06). Median number of premature ventricular contraction (PVC) at baseline was 17 beats per hour in both the HOT and the control groups. Overall improvements of PVCs were not different either in the HOT group or in the control. However, in 12 patients with NYHA >= III and AHI >= 20 events/h, PVC was significantly improved by HOT with a marked reduction in AHI and a substantial increase in LVEF. In conclusion, among patients with CHF and CSA, HOT improves SDB, QOL, and cardiac function. The effectiveness of HOT for ventricular arrhythmias was not observed in the overall analysis, but only in a limited number of patients with severe CHF and SDB. To clarify the effects of HOT on ventricular arrhythmias in patients with CHF and SDB, a further study is needed.