Sudden cardiac death presumably due to cardiac arrhythmias is one of the hypotheses to explain the observed higher cardiovascular mortality in the adaptive servo-ventilation (ASV) group of the SERVE-HF study [1, 2]. In this regard, we congratulate Tamisier et al. [3] for their efforts to clarify the effect of ASV on muscle sympathetic nerve activity (MSNA) in patients with central sleep apnoea (CSA) and heart failure with reduced left ventricular ejection fraction (HFrEF). Analysing data from an SERVE-HF ancillary study, they concluded that: 1) suppression of CSA with ASV did not seem to have a significant effect on chronic HFrEF-related sympathetic activation; and 2) simultaneous suppression of CSA and reduction in MSNA was associated with increased cardiovascular mortality. In our opinion, these conclusions might be different if some confounding factors were considered.