Methods:

This is a prospective, single-center, randomized, single-blind trial. Patients were recruited from both cardiology and sleep medicine practices. Seventy-four HF patients with CSA on CPAP were screened. Inclusion criteria were as follows: 1) previous diagnosis of moderate to severe CSA, defined as apnea-hypopnea index (AHI) ≥15 events/hour, of which ≥50% were central events; 2) on CPAP therapy for ≥3 months but current (within 1 month) AHI on CPAP remained ≥15 events/hour with polysomnography; 3) history of persistent systolic HF (even after CPAP initiation), defined as a left ventricular ejection fraction (LVEF) <50% on echocardiography and New York Heart Association class ≥II; and 4) absence of HF exacerbations while receiving stable-dose optimal medical therapy within the previous 3 months. Exclusion criteria were: 1) age <20 or ≥80 years; 2) HF primarily due to organic valvular heart disease, with anatomic alteration of the valve; 3) need for cardiac resynchronization therapy; 4) chronic obstructive pulmonary disease with ventilatory impairment; 5) need for dialysis; and 6) history of stroke with neurological deficit.