Difference from PA with VSD? 
In this condition, there is no connection between RV and LV as ventricular septum is intact. Most of the times, tricuspid valve (TV) is abnormal in this condition.

Treatment options in this condition? 
Treatment is decided on the basis of size of TV. If TV size is small then RV will be very small and if it is adequate in size then RV will be of adequate in size. If size of RV is adequate then we may palliate the child by perforating the pulmonary valve by intervention (without surgery). If size of RV is small, then blood supply to the lungs will depend on PDA and by doing this if RV can grow in few days to weeks, then two ventricle repairs can be planned. PDA can be opened either by PGE1 (prostaglandin) infusion or by putting a stent into it.

How the child does presents clinically? 
If size of RV is small then there will be tricuspid valve regurgitation and there will be reverse shunting across PFO and child will be blue from early period of life. If size of RV is very very small then RV pressure will be very high and there will be formation of coronary sinusoids in RV. In this condition, coronary circulation will depends on RV and we cannot open pulmonary valve in this situation.

What are other treatment options that we can do in this case? 
Only superior vena cava (draining impure blood from upper part of body) can be connected to pulmonary artery leaving IVC (draining impure blood from lower part of body) drainage into RA (known as one and half ventricle repair). If RV size is also not able to tolerate this then only aspect is to do univentricular pathway treatment (Fontan operation).