NPR3 and pulmonary arterial hypertension: NPR-C-/- mice exhibit important structural features including right atrial and ventricular enlargement, hypertrophy of the right ventricular free wall, tricuspid regurgitation as well as echocardiographic findings suggestive of right ventricular pressure overload manifested as abnormal motion of the interventricular septum, which are all findings typically seen in humans with PAH [1].