Supraventricular tachycardia in infancy and childhood: diagnosis, antiarrhythmic and interventional therapy

Supraventricular tachycardias are the most frequent forms of symptomatic ta chyarrhythmias in infants, children and adolescents. Clinical symptoms depe nd on age and underlying cardiac anatomy. Newborn babies and infants with p aroxysmal atrioventricular reentrant tachycardias usually present with sign s of congestive heart failure due to rapid heart rate. In older children an d adolescents, palpitations are the leading symptom. Patients with chronic- permanent tachycardias (i.e., atrial ectopic tachycardia, permanent form of junctional reciprocating tachycardia) often develop a secondary form of di lated cardiomyopathy, the so-called "tachymyopathy'". Adenosine has evolved as the drug of choice in any age group for the termin ation of atrioventricular reentrant tachycardia of any origin. In addition, it serves as a diagnostic tool in primary atrial tachycardias. Long-term m anagement of atrioventricular reentrant tachycardia in infancy and childhoo d is age dependent. In newborn babies and infants, pharmacological therapy is advised due to the high spontaneous cessation rate of those tachycardias at die end of the first year of life. In contrast to this, the probability of spontaneous cessation of tachycardia in children >1 year of age is very low. Therefore, radiofrequency catheter ablation of the anatomical substra te of the tachycardia is a rational alternative to long-lasting antiarrhyth mic therapy. Results in children with a structurally normal heart are compa rable to those achieved in adults. In patients with congenital heart diseas e and supraventricular tachycardias, catheter ablation during preoperative cardiac catheterization is recommended. Atrial reentrant tachycardias have been identified as one major risk factor for late postoperative morbidity and mortality in young patients. Pharmaco logical therapy is often not sufficient to control the tachycardia. In addi tion, underlying sinus node dysfunction may be aggravated in a considerable portion of the patients affected. Catheter ablation based on conventional endocardial mapping techniques by multipolar electrode catheters with the a im of identifying the critical region of the reentrant circuit is associate d with an impaired success rate and a consider able recurrence rate. It may be assumed that, using the modem mapping techniques currently available (e lectroanatomical mapping and non-contact mapping), results of radiofrequenc y catheter ablation of atrial reentrant tachycardias after surgical correct ion of congenital heart disease will be significantly improved within the n ext few years.