Invasive electrophysiologic studies in children.

Although the technique of performing invasive electrophysiologic studies is similar in children and adults, the indications, interpretation, and management based on the studies are different. The major indications in children are determination of the specific diagnosis of an unknown arrhythmia and mapping prior to surgical treatment; chronic drug studies are performed for severely symptomatic patients, but technical considerations in the child limit the routine use of repeated drug trials. The greatest potential indication for invasive studies is in prognostication of symptomatic arrhythmias; this has not been possible in sinus node dysfunction and AV block, and the role in ventricular arrhythmias is under investigation. In the area of therapeutics, although drugs may have a similar effect in adults and children, the mechanism for the underlying arrhythmias may differ. The ventricular arrhythmias after congenital heart disease may have as their underlying cause the hypertrophic ventricle, not the pediatric substrate. Thus, some of the investigations originally performed in children eventually may contribute to a better understanding of arrhythmias in patients of all ages.