Developmental Aspects of Long QT Syndrome Type 3 and Brugada Syndrome on the Basis of a Single SCN5AMutation in Childhood

We conclude that electrocardiographic characteristics of LQT3 and BS show age-dependent penetrance. A QT prolongation and conduction disease were present from birth onwards, whereas ST-segment elevation only developed >5 years. Good tools for clinical diagnosis of LQT3 in this family are QTcat the lowest HR and ΔQT after a pause in a Holter, even at very young age.