Patients with CHF frequently suffer from CompSA, predominantly CSA/HCSB and components of OSA. Moreover, the proportion of CSA/HCSB vs OSA contributing to the overall apnea-hypopnea index (AHI) may vary with body position, time during the night, and sleep state. In a large number of these patients, CSA is not suppressed with CPAP use, and we recommend ASV therapy. CPAP, however, is the treatment of choice in patients with heart failure and exclusively (or perhaps predominantly) OSA, although CSA13,14 may emerge with the use of this therapeutic modality as we observed in an early study.13 In a study comprising 192 patients,14 the prevalence of CompSA was estimated at 15%. The patients demonstrating CompSA were found to exhibit heightened CO2 chemosensitivity, which has been shown to predispose to PB by increasing loop gain.15,16 In as many as 53% of patients with CHF and heart failure with reduced ejection fraction (HFrEF), CSA is not suppressed during the first night of CPAP titration,13 and this finding usually persists, with prevalence declining only slightly to 43% at 3 months.17 At present, it is not possible to accurately predict whether a given patient will exhibit CSA/HCSB on CPAP. One study found that a low Paco2 may be a surrogate for high loop gain and CPAP nonresponsiveness, but this was not an invariable relationship.13 Further prospective studies phenotyping patients with heart failure are needed to determine whether high loop gain and low Paco2 reliably predict CPAP nonresponse and obviate the need for a trial of CPAP titration. At present, we recommend continued use of CPAP only in patients in whom CSA is suppressed during the initial titration.13,17 We recommend ASV titration when CSA/HCSB persists during the initial CPAP titration because we believe that continued use could be detrimental.7-11,17 To emphasize, even though a small proportion of patients with CHF will exhibit resolution of CSA/HCSB over time when central events are not initially suppressed by CPAP therapy, the high failure rate (43% at 3 months)17 and the inability to predict long-term success suggest that it is not beneficial to recommend CPAP therapy if the AHI does not fall to < 15/h on the first night of titration.