Junctional Ectopic Tachycardia Localization and Procedural Approach using Cryoablation

Abstract

In the majority of patients JET can be safely ablated with the use of cryotherapy. Foci not identified in the lower 2/3 of the TOK are associated with longer procedures, more lesions, and decreased chance for long-term success.

Junctional ectopic tachycardia in infants and children

“…Characteristics of JET include the lack of resetting or termination of the tachycardia during His-refractory atrial extrastimulus pacing or a His-atrial time which is longer with ventricular pacing than during the arrhythmias. 2,22,24 If an atrial extrastimulus is delivered during tachycardia and advances the timing of the His immediately following without terminating the tachycardia, this indicates that a retrograde fast pathway is not required for the maintenance of the tachycardia, thus confirming the mechanism as JET. 24 Overdrive pacing during tachycardia can be used to differentiate from reentrant arrhythmia.…”

“…21 The diagnosis of JET can be confirmed by VA disassociation during JET noted with either ambulatory monitoring or during the EP study, and reinforced with the typical rate variability associated. 22 Occasionally, the tachycardia might be irregular, thus resembling atrial fibrillation. Rates for JET can vary over time in response to adrenergic state, and occasional irregularity may be seen owing to capture beats from dissociated sinus rhythm.…”

“…Enhanced automaticity can also occur, however, as suggested by the ability of this tachycardia in some patients to accelerate with enhanced sympathetic tone. 2,[22][23][24][25] The arrhythmia usually is not inducible by a single extrastimulus, cardioversion, or by programmed electrical stimulation, thus making reentry an unlikely mechanism. (Figure 3).…”

Look and you shall find: Perils along the road after slow pathway ablation for AV nodal reentry tachycardia

“…23 Successful ablation of JET in pediatric patients can be achieved in the slow pathway region without producing direct AV nodal injury. 24 How might JER/JET come about following slow pathway ablation and how might we explain Kusterer et al's observations? 15 Bailin et al have used detailed voltage mapping in the triangle of Koch to identify a low voltage region, which has been termed the low voltage bridge.…”

“…The occurrence of JET in pediatric patients with surgical complete AV block has been reported as a good prognostic predictor of future recurrence of intact AV conduction . Successful ablation of JET in pediatric patients can be achieved in the slow pathway region without producing direct AV nodal injury …”