Experience with flecainide for the treatment of cardiac arrhythmias in children

We treated 22 children, aged 3 days to 16 years 6 months (medium 11 years 1 month), with flecainide for a variety of aryhythmias where a Class I agent was indicated in 16, conventional antiarrhythmic treatment had failed. Structural heart disease was present in nine. The arrhythmia was paroxysmal re-entry atrioventricular tachycardia in five and frequent ventricular extrasystoles (with couplets) in three. Sinas rhythm was achieved in all four children who received flecainide during tachycardia (three received intravenous flecainide during tachycardia (three received intravenous flecainide, one oral). During follow-up of 3–24 months (median 12 months), arrhythmia control was obtained in 13 children (59%). Combination therapy was used in seven of these; with digoxin in four and a beta blocker in three. Flecainide doses used in this study ranged from 1–11 mg kg−1 day−1 (median 4 mg kg−1 day−1), 25–297 mg m−2 day−1).The medium, pre-dose flecainide concentration in those responding to therapy was 225 μgl−1 and in those failing to respond was 417 μgl−1. An arrhythmogenic effect occured in one child.