• Persistent junctional reciprocating tachycardia (PJRT) occurs in children and is characterized by an incessant & sometimes even permanent narrow complex tachycardia 
• PJRT also occurs in adults but in about half these patients it is paroxysmal rather than incessant/permanent
• PJRT is a form of orthodromic AVRT and is caused by a concealed slowly conducting decremental accessory pathway
• Unlike accessory pathways of Wolff Parkinson White syndrome in children that are associated with a structural heart defect in about 1/3 of patients accessory pathways of PJRT are generally isolated
• PJRT can be a serious arrhythmia, particularly in children because of tachycardia-induced cardiomyopathy (TIC) - deterioration of ventricular contractile function caused by very prolonged periods in tachycardia
• LV dysfunction generally resolves following successful ablation of the tachycardia and is indicated even in the very young when the rate is not controlled and especially in patients with persistent left ventricular dysfunction.

References