Electrophysiologic studies of supraventricular tachycardia in children. I. Clinical-electrophysiologic correlations.

We investigated the clinical features, surface ECG findings, associated with congenital heart disease (CHD), and status at follow-up in 103 children who underwent intracardiac electrophysiologic evaluation of supraventricular tachycardia (SVT). Age at catheterization ranged from 2 days to 17 years (mean 4.2 years). Diagnosis of the mechanism was based upon standard electrophysiologic techniques. Of the 103 patients, 37 had reentry without a bypass tract (10 sinoatrial node, two atrial muscle, and 25 atrioventricular node); 51 had reentry with a bypass tract (28 manifest Wolff-Parkinson-White [WPW], 18 unidirectional retrograde accessory pathway [URAP], an five Lown-Ganong-Levine); and 15 had an ectopic focus (11 atrial, four junctional). Distinguishing features among the common types are depicted in Table III. We conclude that in children the various mechanisms of SVT (1) are likely to be found in different clinical situations, (2) have a different potential for surgical cure, and (3) have a different prognosis for long-term treatment. Since curative surgery was theoretically possible in 57% of our patients (WPW, concealed WPW, atrial, and junctional ectopic), we recommend electrophysiologic study in any patient who has had frequent recurrences of SVT for longer than 1 year and who requires drugs in addition to digoxin for treatment.