We greatly appreciate the comments made by S. Teramoto and co-workers. In our study 1 we suggested that spectral analysis of heart rate in patients with mild-to-moderate heart failure could be of value in ruling out severe sleep-disordered breathing (SDB), and its use could reduce the burden on sleep laboratories screening for SDB in the heart failure population. However, we stressed that further prospective validation was required and discussed in depth the limitations of spectral analysis of heart rate variability (HRV) as a rule-out test for SDB in heart failure. The key limitation is that it cannot be applied to heart failure patients with atrial …