Ethmozine (moricizine HCl): a promising drug for "automatic" atrial ectopic tachycardia.

Atrial ectopic tachycardia is an uncommon life-threatening supraventricular tachycardia in children and is resistant to usual antiarrhythmic drugs. Whereas the cellular mechanism of atrial ectopic tachycardia is unknown, atrial ectopic tachycardia may be due to a form of automaticity. Moricizine HCl has been used primarily for ventricular rhythm disturbances; the drug depresses abnormal automaticity and delayed after-depolarizations but has little effect on normal automaticity. Because of this property, we have used moricizine HCl in 4 patients with atrial ectopic tachycardia. As evidenced by continuous 24-hour Holter monitoring, moricizine HCl was successful in suppressing atrial ectopic tachycardia in each patient. During a limited follow-up (6 months) no side effects have occurred. Moricizine HCl is a promising primary drug for atrial ectopic tachycardia.