[Mid-term clinical condition and prognosis in adrenergic ventricular tachycardia in children with apparently normal hearts]

Ventricular tachycardia is the most common diagnosis among children with exercise or emotion-related syncope. The aim of the study was to assess the prognosis and the clinical course of children, without long QT syndrome, with exercise-related ventricular tachycardia and apparently normal heart.

Since January 1984, we studied 14 children (mean age 9.7 +/- 3.8 years) with exercise-related ventricular tachycardia, and, at the initial detection, without demonstrable heart disease, as assessed by clinical evaluation, electrocardiogram and mono-bidimensional echocardiogram. Six patients had exercise related syncope, 1 exercise intolerance and 7 were asymptomatic. All patients underwent exercise testing on treadmill and 24-hour ECG monitoring. All patients were treated with antiarrhythmic drugs. All patients were tested by exercise testing and 24 hour ECG monitoring, alternatively, every six months, during therapy or after complete wash-out of the drug used.

Ventricular tachycardia, detected by exercise testing and Holter monitoring, was polymorphic in 4 symptomatic patients, monomorphic with left bundle branch block morphology and inferior axis in the others. The mean rate of monomorphic ventricular tachycardia was 224 +/- 35 bpm in the symptomatic children and 180 +/- 33 bpm in the others (p = 0.03). Successful chronic treatment was achieved with beta-blockers in 5 cases, propafenone in 6, sotalol in 2 and flecainide plus metoprolol in 1. During follow-up (6 +/- 2.7 years), 1 patient with polymorphic ventricular tachycardia, on therapy, suddenly died during exercise, the other symptomatic patients had no variation of their arrhythmia on routine tests, except 1 who, after propafenone was stopped, had ventricular fibrillation during exercise testing. Among the 7 asymptomatic patients, 5 had no evidence of ventricular tachycardia on routine test after 2 +/- 3 years; the others had no variation of their treatment.

Exercise related ventricular tachycardia in children seems: 1) to have more severe prognosis if symptomatic or polymorphic; 2) mostly to arise from right ventricle; 3) to be successfully treated by antiarrhythmic drugs with beta-blocking activity.