The purpose of this feasibility study is to assess whether an alternative transvenous lead location affects respiration and airway physiology during a commercial remedē® System or commercial transvenous cardiac device (de novo pacemaker or implantable cardiac defibrillator) implant procedure.

Inclusion Criteria:

• Subject is at least 18 years old
• Subject with moderate to severe central sleep apnea is undergoing a de novo commercial remedē® System implant procedure or other de novo transvenous cardiac implantable device procedure including a pacemaker or an implantable cardiac defibrillator
• Subject is willing and able to give informed consent

Exclusion Criteria:

• Subject is unable or unwilling to participate with study procedures or in the investigator's opinion is medically unstable for the procedure (Medically unstable is defined as when a patient is expected to have worsening health status if additional procedure time is needed)
• Subject is pregnant or planning to become pregnant (all women with childbearing potential must have a negative pregnancy test within 7 days prior to the implant)
• Subject is known to be allergic to radio opaque dye which cannot safely be pre-treated per the investigator
• Subject has body mass index (BMI) > 40 kg/m2 at the time of implant
• Subject has had prior neck surgery
• Previous or currently implanted upper airway stimulation device
• Subject has had prior oral cavity surgery that may interfere with breathing
• Subject has significant upper airway-related anatomic anomaly
• Subject is enrolled in concurrent study that may confound the results of this study
• Subject is taking muscle relaxant medication unless approved by the site implanter and ZOLL Respicardia clinical staff
• Subject has evidence of nerve weakness/paresis/paralysis or a neurologic disorder that involves the tongue