Atrioventricular reentrant tachycardia (AVRT) is the most common cause of supraventricular tachycardia in young children. In nearly 70% of cases, there is manifest preexcitation on electrocardiogram. In the rest, the accessory pathway is concealed. Drugs control AVRT by affecting conduction through the atrioventricular node (beta-blockers, digoxin, verapamil) or accessory pathway (flecainide, propafenone) or both (sotalol, amiodarone). Adenosine is the drug of choice in acute management of AVRT in hemodynamically stable children. In adenosine-resistant cases, intravenous flecainide, procainamide, esmolol, propafenone and amiodarone are other treatment options. Hypotension and bradycardia can occur during administration of these drugs. Verapamil may be used to treat AVRT using a concealed pathway. Verapamil should be avoided in infants and in patients with decreased cardiac function. In chronic management, catheter ablation is the preferred treatment in older children with frequent AVRT. In infants and small children, ablation is associated with higher risk, and pharmacologic management is recommended. Beta-blockers are the preferred first line drugs for chronic management. In patients with concealed accessory pathway, digoxin and calcium channel blockers are alternative options. Sotalol, flecainide, propafenone and amiodarone can be prescribed in resistant cases. Flecainide and propafenone should be avoided in children with structurally abnormal hearts because of a higher risk of proarrhythmia. The initiation of flecainide, propafenone and sotalol therapy is recommended in an inpatient setting to monitor for proarrhythmias.
