TETRALOGY OF FALLOT
Most common cyanotic ocngenital disorder and most common cause of blue baby syndrome
R to L shunt
Clubbing with cyanotic nails
Polycythemia
1-Pulmonary infundibular stenosis
2-Overriding aorta
3-VSD
4-RVH

Pulmonary infundibular stenosis is most likely due to hypertrophy of the septoparietal trabeculae. It can
occur at the PV or just below it.
The degree of stenosis is the 1ary determinant of severity and
symptoms. Overriding Aorta is an aortic valve with biventricular connection above the VSD.
The
aortic root can be displaced anteriorly but it is always abnormally located to the right of the pulmonary root.
RVH can cause acharacteristic
Bootshaped heart (Coeur en Sabot) on CXR.  
VT post TOF Repair
SCD up to 5% during follow-up

Risk Factors
ECG Baseline: QRS> 180 ms - Frequent PVCs
Older age at repair
Transannular RVOT Patch
LV dysfunction
+ EPS
RVSP
Symptoms

Around ventriculotomy scar: either LBBB/superior or RBBB/inferior
Ablation:
-Linear ablation from ventriculotomy scar to PV annulus or TV annulus if macroreentrant circuit proven by
entrainment at isthmus site
-Focal ablation target earliest presystolic activity with concealed entrainment documented

Pre ablation do a voltage map: usually you will see a low voltage scar involving the entire RV basal wall.
A large reentrant circuit => entrainment with concealed fusion