The overall purpose of this study is to determine the effects of adaptive servo ventilation (ASV) and bi-level ventilators on Cheyne-Stocks respiration (CSR). CSR is a pattern of breathing characterized by hyperpneas followed by hypopneas and or apneas. Clinically, the physiologic changes translate to sleep fragmentation, excessive daytime sleepiness, reduced exercise capacity and possibly ventricular arrhythmias. The intent of the proposed intervention is to compare the efficacies of ASV and Bi-level ventilator on CSR.

Inclusion Criteria:

1. Patient or legal representative of the patient is willing and able to sign an IRB/MEC approved informed consent and Privacy Protection Authorization in the United States

2. Subject is > 18 years old

3. Patients with known history of CSR. CSR symptoms may include the following:

   • sleep fragmentation as reported by patient or as witnessed by another person
   • night arousal after apneic episodes
   • reduced exercise capacity
   • daytime sleepiness

4. Expected to tolerate the ventilator therapy

Exclusion Criteria:

1. Baseline oxygen saturation < 90% on a stable FIO2)
2. Patient is currently enrolled in another clinical study which may confound the results of this study
3. Patient for whom informed consent cannot be obtained
4. Patient who is of pregnant or of child bearing potential without a negative pregnancy test within 10 days of the study procedure
5. Patients implanted with unable to tolerate inactive pacemaker, implantable defibrillator or cardiac resynchronization device for duration of testing procedure - approximately 8 hours (e.g. pacemaker dependency)
6. Patients with severe COPD (per GOLD scale)
7. Patients with a history of myocardial infarction within the 6 months prior to the study
8. Patients with unstable angina

Patients with both CSR and heart failure