Step away from the jump: sustained slow conduction in pediatric atrioventricular nodal reentrant tachycardia.

摘要

AV nodal reentrant tachycardia (AVNRT) is an important arrhythmia at all ages. Though relatively uncommon in infants and young children, by adolescent and teenage years AVNRT comprises 40-50% of Supraventricular tachycardia (SVT). The clinical and electrocardiographic features of the typical form of AVNRT are well characterized and include a short VA interval during tachycardia, concentric atrial activation, and an inability to advance atrial activation by ventricular premature beats delivered when the His-bundle is refractory. Additionally, the potential to observe dissociation of ongoing tachycardia from the ventricles (usually in the form of 2:1 AV block), or less commonly the atria, are useful though inconsistent findings.The additional finding of the so-called "dual AV node physiology" (defined as an increment of > 50 msec in the His-atrial interval (HA) conduction time in response to successive atrial extrastimuli delivered in decrements of 10 msec) is observed in most but not all adult patients with AVNRT. However, this finding is neither a specific nor sensitive finding, as it may be observed among patients with no known history of AVNRT. Indeed, among younger patients, the classic pattern dual AV node physiology may be observed less commonly than among older teenagers and adults.