Post-hoc diagnosis of congenital long QT syndrome in patients with tetralogy of Fallot.

This report describes two patients diagnosed with congenital long QT syndrome after surgical repair of tetralogy of Fallot. Despite the fact that both patients had preoperative electrocardiograms demonstrating QT prolongation, neither was diagnosed until long after their surgeries, when they or their relatives presented with symptoms of long QT syndrome. A brief discussion highlights the reasons why long QT syndrome may be overlooked in patients with structural heart defects and the clinical importance of identifying these patients preoperatively.