Source:Pfammatter J, Paul T, et al. Idiopathic ventricular tachycardia in infancy and childhood.
J Am Coll Cardiol.
1999
;
33
(7):
2067
–2072.

Ventricular tachycardia (VT) is an uncommon disorder in children, especially in those with structurally normal hearts, and guidelines for care are not established. This retrospective, multi-center study, conducted by the Association for European Pediatric Cardiology, evaluated the clinical profile and outcome of pediatric patients with idiopathic VT. Ninety-eight patients from 13 centers were found to have either sustained or non-sustained VT of undetermined etiology while 29 patients with long QT syndrome, catecholaminergic VT, or accelerated ventricular rhythm were excluded. VT was diagnosed by 12 lead ECG or Holter. The mean age of patients was 5.4 years (0.1 to15.1) and 27 patients were 12 months or less. Fifty-three patients (54%) were male. Thirty-six patients (37%) had sustained VT and in 8 the tachycardia was incessant. The tachycardia rate was higher in infants (mean 206) compared to older children (mean 172). A left bundle branch (LBBB) pattern was observed in 70% (P<.01) indicating a right ventricular origin in the majority of children. Infants (under one year) were more likely to have a LBBB pattern (86%) than older children (68%). Right ventricular origin was less likely to be symptomatic (25%) than left ventricular origin (67%, P<.01) although the rate of the VT was no different. VT of right ventricular origin was also more likely to resolve at follow-up (76% of patients with LBBB pattern resolving vs 37% with RBBB pattern, P<.01).

One-third of patients (37%) were symptomatic and, of these, one-third (33%) had severe symptoms including syncope (n=4) and heart failure (n=8). Importantly, ventricular function was impaired only in symptomatic patients. High-rate or sustained tachycardia was more likely to be symptomatic. There were no deaths in these patients after a mean follow-up period of nearly 4 years. Nineteen patients (19%) continued to have VT, only one of which required medication. Twenty-five percent of patients never required medication, 40% received medication but no longer required treatment, and 24% still required medication. Seven percent (2/27) with VT in infancy still required treatment compared to 21/71 (30%, P<.05) of children with VT. Only 9 children underwent radiofrequency ablation. The authors concluded that VT with a normal heart carries a good prognosis, particularly in infants, and that pharmacologic treatment may not be indicated in asymptomatic patients. A few patients may warrant catheter ablation procedures.

Unlike idiopathic ventricular tachycardia (VT) in adults, most childhood VT in normal hearts is thought to result from automatic or triggered mechanisms rather than cardiac ischemia. Whether the heart is truly normal is a key point in deciding whether or not to treat VT. Hearts that appear normal on exam, chest radiograph, and echocardiogram may still be histologically abnormal. Fulton et al demonstrated fibrotic abnormalities in patients with VT who died unexpectedly.1 Likewise, Friedman et al found biopsy evidence of myocarditis in 26% of patients evaluated for unexplained ventricular arrhythmias, 11/12 of whom had VT.2 Of 7...

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