The study is designed to look at the usefulness and safety of AXS-12 or placebo for the treatment of Narcolepsy. The open-label treatment period is 24 weeks, which will be followed by a double-blind treatment period of 4 weeks, for a total of up to 28 weeks with 13 visits. Narcolepsy is a chronic sleep disorder characterized by overwhelming daytime drowsiness and sudden attacks of sleep. Study staff nor the participants will know if they are receiving a study drug or placebo. Participants will be male or female subjects 15-75 years old with a diagnosis of narcolepsy. Study drug will be administered as a pill.

The current study will investigate the safety, efficacy and pharmacokinetics of serdexmethylphenidate (SDX) compared to placebo in subjects with Idiopathic Hypersomnia (IH). The study may inform about the best dosing regimen, optimal dose range, duration of treatment, and secondary endpoints for a future Phase 3 study.

This is a study to evalaute the device's safety, function, and effects on heart function, and clinical outcomes of using the Edwards APTURE system (study device) in subjects with heart failure.

Major study activities include 3 right heart catheterizations (RHC) with exercise, a computed tomography (CT) scan with contrast, multiple ultrasounds of the heart, labs, and other assessments. The length of subject participation in the study is 5 years and includes 11 research visits.

The information obtained from this study will show how safe and effective this approach is in treating the symptoms of heart failure. Alternative treatment for heart failure depends on the cause, but may include diet and exercise, managing stress, medication (such as medications to treat leg swelling, high blood pressure, or abnormal heart rate), participation in another research study or continuing with current medical therapy

This clinical investigation is a prospective, non-randomized, single-arm, multi-center early feasibility study of the Aria CV Pulmonary Hypertension (PH) System implanted in patients with pulmonary arterial hypertension (PAH). The device will be implanted in the pulmonary artery and the gas reservoir of the device will be in the abdominal cavity. The purpose of this study is to validate that the clinical use of the Aria CV PH System is safe for the patient, and to evaluate its performance in treating patients with PAH. Some procedures involved in the study include but not limited too: Questionnaires, physical exams, right heart catherization, echocardiograms, blood work and more. The study will be conducted in a maximum of 10 centers in the United States. Up to 45 patients will be consented, and up to 15 patients will receive implants. There is a total of 11 visits over the course of 2.5 years for the study. Because this is an investigational device under the FDA, there may be risk that include but are not limited to: arrhythmia, device infection, endocarditis, and heart failure. If the Aria CV device performs as intended, you may potentially benefit from reduction in or relief of symptoms caused by PH, and depending on your overall health conditions, prolonged life expectancy and/or improvement in your overall quality of life.

The purpose of the study is to evaluate the safety and how well the medication levosimenden works versus placebo in treating Pulmonary Hypertension and Heart Failure with a Preserved Ejection Fraction measured by a 6 minute walk. This is a condition where the lower left chamber (left ventricle) of the heart is not able to fill properly with blood during the filling phase and the amount of blood pumped out to the body is below normal. The study will also look at information obtained from the tests performed as part of the study to see if subjects have improvement in symptoms of heart failure. Levosimendan is a drug that has been FDA-approved for intravenous (IV) delivery to your body. This study aims to determine if the tablet form of the drug is as effective as the IV route. Tablets are much more attainable for patients to manage their heart failure from home, rather than going to an infusion clinic for treatments. Participation in this study will last approximately 12 weeks with the option to continue to the stage 2 phase of the study. If the stage 2 phase is selected as well, participation will last approximately 26 months or a little over 2 years. These visits will include such activities as blood tests, questionnaires, physical evaluation by a study doctor, echocardiogram, and 6 minute hall walks.

Participants will be randomized to either the treatment group (and receive the medication) or the control group (receive an inactive medication). Subjects will have a 50:50 chance of receiving the study medication during their participation in the trial. The treatment assignment is determined by randomization, where a computer selects at random which treatment group you will be in (like drawing straws). Neither the subject, nor the blinded personnel will know which group subjects are in. Neither the subject nor the study doctor will decide what group subjects are assigned.