Pre-excitation syndrome in infants and children. Effect of digoxin, verapamil, and amiodarone.

Clinical and electrocardiographic findings for 30 patients with the pre-excitation syndrome are described together with details of treatment. Nineteen (63%) were younger than 2 years, 14 of whom were under 2 months. Sixteen infants and 7 children (77%) presented with paroxysmal supraventricular tachycardia, 14 (61%) of whom had the electrocardiographic pattern of type A Wolff-Parkinson-White (WPW) syndrome. During paroxysmal bouts the QRS complex was normal in 21 patients and wide in two. Six (20%) patients had congenital heart disease often associated with WPW syndrome type B. Seventeen patients were treated with either digoxin or verapamil intravenously to stop tachyarrhythmias. Verapamil was more effective due to the immediate response and lack of adverse effects. The tachyarrhythmias resolved in all the patients and in some of them the WPW pattern resolved later indicating maturation of the conduction tissue with loss of the accessory pathways. Verapamil provides a rapid and safe form of treatment for conversion of tachyarrhythmias since it has no effect on the accessory pathways. Oral amiodarone prevents recurrent tachyarrhythmias resistant to other treatment.