Feasibility Study to Determine the Effects of Phrenic Nerve Stimulation in Patients With Periodic Breathing

Inclusion Criteria: * Patient is 18 years of age or older * Patient has a demonstrated history of periodic breathing (symptoms may include sleep fragmentation, as reported by patient or as witnessed by another person, night arousal after apneic episodes, reduced exercise capacity, and daytime sleepiness) * Patient is expected to be able to tolerate the procedure and remain clinically stable for the duration of the study (e.g. the subject is able to lie down long enough to insert the lead(s) without shortness of breath and the subject is able to tolerate instrumentation during study). * Patient or their legal representative is willing and able to sign an IRB/MEC approved informed consent (and a privacy protection authorization in the United States) Exclusion Criteria: * Baseline oxygen saturation less than or equal to 90% on a stable FIO2 * Evidence of phrenic nerve palsy * Temperature \> 38.0 degrees Celsius * Inability to place catheter (e.g. previously known coagulopathy, distorted anatomy, etc.) * Patient is currently enrolled in another study that may confound the results of this study * Patient for whom informed consent cannot be obtained * Patient who is pregnant or of child bearing potential without a negative pregnancy test within 10 days of the study procedure * Patients implanted with a pacemaker, implantable defibrillator, or cardiac resynchronization device who are unable to tolerate turning off the device for the duration of the system testing procedure (based on medical judgment) * Patients with severe COPD (per GOLD scale) * Patients with a history of myocardial infarction within 6 months prior to the study * Patients with unstable angina * Patients who are intolerant of or allergic to contrast dye * Patients who are contraindicated for \<1mg of steroid (on the stimulation lead).