Comparison of Inhaled Nitric Oxide and Oxygen in Participants Reactivity During Acute Pulmonary Vasodilator Testing

Inclusion Criteria

• •1. Must have any one of these three disease categories:
• •* Idiopathic Pulmonary Arterial Hypertension
• •* Mean pulmonary arterial pressure (PAPm) \> 25 millimeters of mercury (mmHg) at rest, pulmonary capillary wedge pressure (PCWP) ≤ 15 mmHg, and PVRI\> 3 u•m\^2 or diagnosed clinically with no previous catheterization
• •* Congenital heart disease (CHD) with pulmonary hypertension repaired and unrepaired
• •* PAPm \> 25 mmHg at rest and PVRI\> 3 u•m\^2 or diagnosed clinically with no previous catheterization
• •* Cardiomyopathy
• •* PAPm \> 25 mmHg at rest and Pulmonary vascular resistance index (PVRI)\> 3 u•m\^2 or diagnosed clinically with no previous catheterization
• •2. Scheduled to undergo right heart catheterization to assess pulmonary vasoreactivity by acute pulmonary vasodilation testing.
• •3. Male or female, ages 4 weeks to 18 years, inclusive
• •4. Signed informed consent/assent