There is a congenital heart lesion with an initial left to right shunt but then develops pulmonary hypertension and shunt flow reverses
- Increased right-sided pulmonary blood flow causes pulmonary hypertension
- Pulmonary hypertension causes right to left shunting usually due to VSD
- Prevent it with early correction of defect and treatment
- Pregnancy is contraindicated due to a high rate of mortality
- The lungs are a low resistance vascular network supplied by a low-pressure pump - the right ventricle.
- If a VSD or other shunt causes a huge increase in right-sided flow as blood passes from the left-sided high-pressure system to the right and eventually then pulmonary hypertension develops.
- Eventually the pressures across the shunt equalise and deoxygenated blood bypasses into the left-sided circulation.
- Endocarditis prophylaxis is recommended
- Ventricular septal defect: the PSM disappears and replaced by a pulmonary regurgitant murmur
- Atrioventricular canal defect
- Atrial septal defect
- Persistent truncus arteriosus
- Transposition of the great arteries
- Polycythaemia - Gout, Hyperviscosity - use cautious phlebotomy + Aspirin + Allopurinol
- VSD: the PSM disappears and replaced by a pulmonary regurgitant murmur
- Central Cyanosis as Pulmonary hypertension causes right to left shunting
- Finger clubbing, Cerebral embolic phenomena, Endocarditis can develop
- Cholelithiasis, Loud P2
- FBC : polycythaemia
- CXR: prominent central pulmonary arteries, peripheral pulmonary pruning, and right heart enlargement. Pulmonary oligaemia.
- ECG: AF, right ventricular hypertrophy and right atrial hypertrophy
- Echocardigram: raised right-sided pressures, VSD with the right to left shunt
- Right heart catheterisation: elevated right-sided systolic pressures
- Once Eisenmenger's syndrome develops corrective surgery is too late.
- Cardiac transplantation is dubious as the right ventricle of the transplanted heart cannot cope with the raised pulmonary vascular resistance. The only hope is a combined heart-lung transplant.