Tetralogy of Fallot TOF

Discussion on some important aspects of tetralogy of Fallot.
The four cardinal features of tetralogy of Fallot (TOF) are:
1. Malalignment ventricular septal defect
2. Overriding aorta
3. Infundibular pulmonary stenosis
4. Right ventricular hypertrophy
The variability in clinical presentation of TOF correlates with degree of right ventricular outflow tract obstruction and the size/anatomy of pulmonary artery and its branches. They usually present with cyanosis in childhood. Squatting on exertion and cyanotic spells are classical symptoms.