A 42 year old lady had corrective surgery for cyanotic congenital heart disease at the age of 3y, after a palliative operation during infancy. There is a parasternal impulse and an early diastolic murmur. What is the most probable diagnosis?

The key is E. Pulmonary regurgitation. [In the present day, some patients with tetralogy of Fallot have survived for longer than 15-20 years after their first operation. The major problem encountered by these individuals is the development of pulmonary valvular regurgitation. It appears that a number of these individuals require pulmonary valve replacement (ref: Medscape)].