The case of successful elimination of the rare form of a typical atrioventricular nodal tachycardia with episodes of decreemed carrying out and the absence of carrying out at the atrial myocardial
Studies on the mechanisms of atrioventricular nodal reentrant tachycardia have yet to clarify whether the slow and fast pathways connect directly with the atria or via an upper common pathway. Although a "final common pathway" connecting the slow and fast pathways to the proximal His bundle was thought to be part of the reentrant circuit, debate on the presence of an upper common pathway continues. In our report, we present a rare observation of the successful elimination of a typical atrioventricular nodal rientri tachycardia by the slowfast mechanism without the active involvement of the atrial myocardium in the rientri circle in a 51-year-old patient. When studying the electrophysiological characteristics at the time of determining the Wenckebach antegrade point, the transition to slow paths of nodal conduction and the induction of a typical atrioventricular nodal rientri tachycardia by the slow-fast mechanism were observed, but with decreasing conduction of excitation in the retrograde direction according to the Wenckebach Mobitz II periodical type. Then there was a rare phenomenon of the complete absence of any conduction of excitation to the atrial myocardium in the course of a typical atrioventricular nodal rientri tachycardia, which confirms the existence of the "upper common pathway" in this patient. We believe that our observation broadens the understanding of the electrophys- iological properties of this common supraventricular arrhythmia and, therefore, improves the determination of its subtypes.