Too Many Initials
PH = pulmonary hypertension: I use PH since it's easier to say or type, but it's just a general reference to pulmonary hypertension.
PAH = pulmonary arterial hypertension: PAH is when the right side of the heart needs to work harder to get blood pumped through the narrowed arteries in the lungs. If the right side needs to work harder, it becomes enlarged, and can eventually fail.
PVH = pulmonary venous hypertension: PVH is PH due to left heart disease, like systolic dysfunction, diastolic dysfunction, and valvular disease.