Pathophysiological Study of CSA in Adults With pLVEF

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