Incessant SVT in children: Ectopic atrial tachycardia and permanent junctional reciprocating tachycardia

Abstract

Ectopic atrial tachycardia (EAT) and permanent junctional reciprocating tachycardia (PJRT) can cause incessant and medically refractory SVT in children, leading to heart failure and shock. In this review, we discuss the diagnosis, medical treatment, and indications for ablation for these two very different but equally difficult to treat arrhythmias.

Introduction

The vast majority of pediatric tachyarrhythmias are caused by reentrant SVT using dual AV node physiology or an accessory pathway as the basic substrate. This “paroxysmal SVT” (PSVT) depends on critically timed premature atrial contractions (PAC) or premature ventricular contractions (PVC) to initiate tachycardia. These children tend to have episodes of tachycardia that are short lived and easily terminated with adenosine. Since critically timed PACs and PVCs do not come along that often, most children with PSVT have infrequent episodes and once tachycardia is terminated there may be a long interval before another episode is initiated.

EAT and PJRT, by contrast, do not require a critically timed extrasystole for initiation and thus, these types of SVT are more likely to be incessant. Both tachycardias have a long “RP interval” and slightly slower rates than typical PSVT and may be confused with sinus tachycardia at first glance. When incessant tachycardia persists for days, it may lead to tachycardia induced cardiomyopathy (TIC) which can mimic dilated cardiomyopathy in its clinical presentation. A potentially treatable arrhythmia is one of the few reversible causes of cardiomyopathy in children [1], [2] and hence, it is critical to rule out EAT and PJRT in any child presenting with heart failure or for a transplant evaluation.

Chronic tachycardia leads to heart failure through chamber dilation and ventricular dysfunction related to structural and cellular changes caused by rapid heart rates. The degree of dysfunction is directly related to the tachycardia rate and duration with rapid SVT leading to heart failure in as little as 24 h, and slower SVT progressing over days [3], [4]. Although EAT and PJRT are less frequently encountered forms of SVT, they account for a large percentage of tachycardia induced cardiomyopathy encountered in children and infants.