SUPRAVENTRICULAR TACHYCARDIA IN INFANCY A ND CHILDHOOD - DIAGNOSIS AND TREATMENT

Supraventricular tachycardias are the most frequent symptomatic tachyd ysrhythmias in infants and children. The majority of affected children have an otherwise normal heart. Based on the electrophysiologic mecha nism, i.e. reentry or abnormal enhanced automaticity, several differen t forms of supraventricular tachcardias may be differentiated. The tac hycardia most frequently encountered is due to a reentry mechanism bas ed on an accessory atrioventricular pathway either with preexcitation in the surface ECG (Wolff-Parkinson-White-syndrome) or without preexci tation (concealed pathway). The surface ECG recorded during tachycardi a, possibly together with a transoesophageal ECG, allows sufficient ch aracterization of the type of tachycardia. Clear definition of the mec hanism of the tachycardia may be accomplished by invasive electrophysi ologic study. Termination of an acute episode of supraventricular tach ycardia can be achieved effectively and safely with several new antiar rhythmic drugs. Oral antiarrhythmic treatment is performed in order to prevent recurrencies of tachycardia. Knowledge of the tachycardia mec hamism allows specific treatment. In young patients with drug-resistan t tachycardia and/or severe symptoms, electrophysiologic study and cat heter ablation of the arrythmogenic substrate by radiofrequency curren t application offers curative treatment.