This editorial refers to ‘Transvenous phrenic nerve stimulation for the treatment of central sleep apnoea in heart failure’, by P. Ponikowski et al. , doi:10.1093/eurheartj/ehr298 The prevalence of central sleep apnoea (CSA) is 100-fold greater in chronic heart failure (HF) due to impaired systolic function than in the general population.1 It afflicts principally elderly male patients who have atrial fibrillation, implanted pacemakers, low arterial PCO2 when awake, or high diuretic requirements.1 Its presence identifies HF patients with higher night- and day-time sympathetic nervous system activity,2 at increased of risk of malignant ventricular arrhythmias,3 whose survival is foreshortened.4 The primary abnormality in CSA is neither the upper airway collapse of obstructive sleep apnoea (OSA), which can be treated quite effectively with continuous positive airway pressure (CPAP), nor a paucity of ventilation, but rather the compromise of mechanisms that normally stabilize breathing due to the confluence of pulmonary congestion, circulatory delay, altered cerebrovascular blood flow, and enhanced central sensitivity to CO2, all predisposing to hyperventilation.4 Although the reality is more complex, to simplify, in HF the cyclical oscillations between hyperpnoea and apnoea, known commonly as Cheyne–Stokes respiration, are initiated by the hyperpnoea, which can be stimulated by spontaneous arousal from sleep, or by pulmonary congestion. During sleep, the latter is exacerbated both by fluid shifts from the periphery to the cardiopulmonary reservoir,5 and by pre-existing pulmonary–cardiac–chemoreceptor circulatory delay. Thus, when increases in pulmonary capillary and venous pressures stimulate pulmonary irritant receptors, triggering a bout of hyperpnoea, the already low PaCO2 is driven below the patient's apnoeic threshold. Central drive to the muscles of breathing pauses until the rising PaCO2 and falling PaO2 are sensed, eventually, by chemoreceptors, which then initiate a new cycle of hyperpnoea, hypocapnia, and apnoea. CSA is …