EXPERIENCE WITH MORICIZINE HCL IN CHILDREN WITH SUPRAVENTRICULAR TACHYCARDIA

Eight children, age between 4.5 and 19 years were treated with moriciz ine for supraventricular tachycardia during the last 3 years. The tach ycardia was documented by surface electrocardiogram (EGG), and/or by a mbulatory ECG in all the children and the mechanism of tachycardia was determined by previously published surface ECG and electrophysiologic criteria in all but one child. Of the eight children, three had atria l ectopic tachycardia, three had automatic junctional ectopic tachycar dia, one had atrioventricular (AV) nodal reentry tachycardia and one h ad atrial reentry. All the children except one had failed trial of two or more antiarrhythmic drugs prior to moricizine therapy. The duratio n of moricizine therapy ranged from 4 days to 25 months. In three of t he eight children (patients 3, 5 and 7), who presented with AV nodal r eentrant tachycardia, automatic junctional ectopic tachycardia and atr ial ectopic tachycardia, respectively, moricizine therapy was effectiv e in restoring sinus rhythm and controlling the clinical tachycardia. Only one child (patient 1) developed proarrhythmia, an episode of fast , narrow-QRS supraventricular tachycardia lasting for 30 s, on the thi rd day of therapy. This was subsequently confirmed by electrophysiolog ic study to be AV nodal reentrant tachycardia. The other side effects noted were non-cardiac, not dose-dependant and did not require dis-con tinuation of therapy. Based on our small series and those of others, m oricizine, a newer class I anti-arrhythmic agent, has a limited but us eful role in the management of recalcitrant type of supraventricular t achycardia, such as ectopic atrial and junctional tachycardia in child ren.