Eisenmenger syndrome causes pulmonary hypertension and is a part of congenital heart disease.
A ventricular septal defect is created that is a large hole in the heart. It is between two lower heart chambers called ventricles.
The hole disrupts the blood flow and mixes the oxygen rich blood with oxygen poor blood.
Blood returns to the lungs and won’t be going to the rest of the body.
This causes pulmonary hypertension due to the increased flow in the pulmonary arteries.