PH = pulmonary hypertension, a general term used to describe PH.
PAH = pulmonary arterial hypertension, which means the right side of the heart is affected. PAH can be treated by 9 currently available FDA-approved PH meds.
PVH = pulmonary venous hypertension, which means the left side of the heart is affected. Unfortunately, for PVH, many of the treatments available for PAH cannot be used to treat symptoms. These meds can actually worsen PVH patients.
Hope this isn't too confusing!!