Prospective Evaluation of Heart Failure Patients With Central Sleep Apnea

This trial is a prospective, non-randomized observational study in heart failure patients
with moderate to severe central sleep apnea (CSA).

Inclusion Criteria:

- Subject is willing and able to comply with this protocol and has signed an IRB/MEC
approved informed consent (as well as Privacy Protection Authorization in the United
States)

- Age is greater than or equal to 18 years

- Known recent history of sleep disordered breathing of predominantly central origin,
as evidenced by an overnight PSG with EEG and at least 4 hours of recording that was
conducted within 60 days of enrollment and demonstrating the following
characteristics:

- AHI greater than or equal to 20

- greater than or equal to 50% of classified events of a central nature

- less than 20% of the total AHI comprised of obstructive apnea events

- Diagnosed chronic heart failure, with medications optimized and stable for at least
30 days prior to the screening PSG, or since the date of the earliest test used for
baseline, whichever is longer. Optimal medications include: beta blockade, ACE-I or
ARB and diuretics unless contraindicated or not considered medically necessary.

Exclusion Criteria:

- Current or intended use of any mask-based therapy for central sleep apnea

- Baseline oxygen saturation less than or equal to 90% on a stable FiO2

- Severe Chronic Obstructive Pulmonary Disease (COPD) (per GOLD classification system)

- History of cerebrovascular accident (CVA), myocardial infarction (MI), coronary
artery bypass grafting (CABG) surgery, or percutaneous coronary intervention (PCI),
or any cardiac ablation procedure within the 3 months prior to the study

- Unstable angina

- History of primary pulmonary hypertension

- Currently enrolled in a non-observational (ie, interventional) clinical study that
could confound the results of this study

- If subject has an implanted cardiac resynchronization device (CRT), it must have been
implanted at least 3 months before enrollment; any other device must have been
implanted at least 30 days prior to enrollment

- Life expectancy of less than 6 months