Pathophysiological Study of CSA in Adults With pLVEF

Sleep apnea is classically divided into obstructive and central apnea, according to the persistence or otherwise of respiratory movements and the existence or not of pharyngeal collapse during apnea. However, there is evidence to suggest that some mechanisms are common to both types of apnea. Although the pathophysiology of obstructive apnea has been the subject of much work and now seems fairly well known, there is much less data on central apnea. These apneas can occur in different comorbid contexts. They are more frequently present in patients with heart failure, regardless of the etiology, and are associated with an adverse prognosis. The investigators hypothesize that the physiopathology of adult central apnea syndrome involves, in addition to ventilatory control abnormalities, upper airway abnormalities (VAS). The objective is to study the pathophysiology of central SAS, by first comparing the collapse of VAS of central apneic patients to those of patients with simple snoring or obstructive sleep apnea. In a second step, the investigators will analyze the cardiorespiratory coupling and will establish a map of the respiratory neural network in patients with central apnea. The investigators will focus their study on patients with central SAS (with preserved systolic heart function) due to the epidemiology of SAS.

A non-randomized case-control comparative monocentric physiopathology study with 3 parallel groups (one group of cases and two control groups) matched for age and body mass index (individual 1: 1: 1 match), to evaluate changes in the collapse of VAS in central apnea ("central SAS case"), compared to subjects without central apnea ("obstructive SAS" and "single snoring"). Primary objective : Evaluation of changes in upper airway collapse in patients with central sleep apnea syndrome with preserved LVEF heart failure ("central SAS case"), compared with snoring subjects free from sleep apnea syndrome ("Simple snoring witnesses") Secondary objectives : * Study the collapsibility of VAS according to the type of apnea ("central SAS case" versus "obstructive SAS case"). * To study the association between the collapsibility of VAS and the global and central apnea-hypopnoea index (IAH). * Study the association between the type of disorder ("central SAS case" versus "simple snoring controls", "central SAS case" versus "obstructive SAS controls") and cardiorespiratory coupling. * Study the association between the type of disorder ("central SAS case" versus "simple snoring controls", "central SAS case" versus "obstructive SAS controls") and the CO2 response slope. * Establish a map of the respiratory neural network in patients with central SAS with preserved ejection fraction. * Study the association between the volumes in acoustic pharyngometry and the values of the Pcrit