CATECHOLAMINERGIC POLYMORPHIC VENTRICULAR-TACHYCARDIA IN CHILDREN - A7-YEAR FOLLOW-UP OF 21 PATIENTS

Background Primary ventricular tachyarrhythmias are rarely seen in chi ldren. Among them, catecholaminergic polymorphic ventricular tachycard ia has a poor spontaneous outcome. Its diagnosis is often delayed afte r the first symptoms, which is unacceptable because treatment with the appropriate beta-blocker prevents sudden death. Methods and Results W e observed 21 children (mean+/-SD age, 9.9+/-4 years) at the time of t he diagnosis who had no structural heart disease and a normal QT inter val on routine EGG. They were referred for stress- or emotion-induced syncope related to ventricular polymorphic tachyarrhythmias. The arrhy thmia, consisting of isolated polymorphic ventricular extrasystoles fo llowed by salvoes of bidirectional and polymorphic tachycardia suscept ible to degeneration into ventricular fibrillation, was reproducibly i nduced by any form of increasing adrenergic stimulation. There was a f amilial history of syncope or sudden death in 30% of our patients. On receiving therapy with the appropriate beta-blocker, the patients' sym ptoms and polymorphic tachyarrhythmias disappeared. During a mean foll ow-up period of 7 years, three syncopal events and two sudden deaths o ccurred, probably due to treatment interruption. Conclusions The entit y of adrenergic-dependent, potentially lethal tachyarrhythmia with no structural heart disease deserves to be individualized. It may form a variant of the congenital long QT syndrome in which the ECG marker is lacking; this primary ventricular arrhythmia must be looked for in a p ediatric patient with stress- or emotion-induced syncope because only beta-blocking therapy can prevent sudden death and therefore must be g iven for the patient's lifetime.