Inclusion Criteria:  Clinically diagnosed pulmonary arterial hypertension (PAH) in any PAH subtype Hemodynamic evaluation at rest at any time prior to or at the index date fulfilling all of the criteria below: a) Mean pulmonary artery pressure greater than (>) 20 millimeters of mercury (mmHg), and b) Pulmonary artery wedge pressure or left ventricular end diastolic pressure less than or equal to (<=) 15 mmHg, and c) Pulmonary vascular resistance greater than or equal to (>=) 3 Wood Units (that is, >= 240 dynes seconds per centimeters penta [dyn∙sec/cm^5]) Newly initiating 1 or more PAH therapy(ies) at index date All mandated assessments must be performed and recorded at the baseline visit before the initiation of the new PAH therapy at the index date For the pulmonary arterial hypertension-symptoms and impact (PAH-SYMPACT) substudy only: Participants initiating any endothelin receptor antagonist (ERA) or phosphodiesterase-5 inhibitor therapies at index date or at therapy change must provide consent to enroll in the optional PAH-SYMPACT substudy. Refusal to give consent for the optional PAH-SYMPACT substudy will not exclude a participant from participation in the main study  Exclusion Criteria:  Participants enrolled in any interventional clinical trial with an investigational therapy in the 3-month period prior to index date Any PAH therapy initiated at index date was used by the participant (including different route of administration of the same compound) within 3 months prior to index date for any reason. (Administration for vasoreactivity testing is permitted)