Residual shunts after tetralogy of Fallot repair: two case illustrations and echocardiographic insights

Residual shunts after tetralogy of Fallot (TOF) repair are rare and can stem from residual defects, unrecognized VSDs, or, rarely, acquired coronary cameral fistulas (CCFs). Correctly distinguishing these is vital since treatments differ.

Two paediatric cases following TOF repair are described: one shows features of an acquired CCF with continuous flow from the coronary artery into the right ventricle. Because of the low shunt fraction, asymptomatic presentation, and lack of guidelines for definitive treatment, the patient is managed conservatively with regular monitoring. The other case, though asymptomatic, demonstrates a significant residual VSD with holosystolic flow; increased pulmonary blood flow and a significant shunt on cardiac catheterization indicate the need for catheter closure.

Acquired CCF is a rare, usually asymptomatic complication managed conservatively, while residual VSDs may cause significant haemodynamic issues requiring intervention. Echocardiography, assessing flow timing, jet origin, and haemodynamics, is key for differentiation.