Clinical Research Directory

Inclusion Criteria: * Men and Women Veterans with central sleep apnea, defined as Apnea Hypopnea Index (AHI)\>15/hour with CAHI\>5/hour, will be included with the experiments. * Those with chronic, stable heart failure with reduced ejection fraction, receiving stable optimized guideline-based therapy and no hospitalizations or change in the medical regimen for the past 90 days before enrollment. Exclusion Criteria: * less than 18 years old * pregnant or breastfeeding females * moderate or severe obstructive or restrictive lung disease, including supplemental o2 use * current treatment for CSA, including any form of PAP in the past three months, or phrenic nerve situation. * too ill to engage in the study procedures, inability to provide consent for participation. * a history of cardiac arrhythmia * Alcohol or substance abuse (less than 90 days sobriety) or current participation in a treatment program * depression or a history of suicidality * severe insomnia (ISI\>21) or reported short sleep duration (\<6 hours) * PAP-emergent central sleep apnea * Lack of PAP acceptance/adherence after a one-week home PAP trial after enrollment. Additional Trazodone Exclusions: * Prolonged QT on baseline ECG, using medications that inhibit CYP3A4 * Patients with severe renal impairment (GFR \< 20ml/min/1.73m2) or end-stage renal disease