Ventricular septal summit stimulation in atrlo-ventricular nodal reentry tachycardia

Abstract

In all, 18 consecutive patients with atdoventricuiar nodal reentry tachycardia (AVNRT) underwent right ventricular (RV) stimulation duling AVNRT from either the RV apex or summit. Stimulation from the RV apex advanced the tachycardia with the same atrial sequence in 8 of 18 patients (33%), hut never concl@vely excluded the m ence of a low atrial tachycardia. RV summit stimulation resulted in direct stimulation of the low septal rim atrium in 8 patients. RV summit stim ulaticn advanced the tachycardia in 4 patients, de layed it in 2 and terminated R in 3 without an atrial electrogram. The latter 2 fmdings exclude the presence of a low atrial tachycardia. Thus, in ps tients with AVNRT, application of extrastimuli closer to the putative reentrant site enables greater efficacy in tachycardia resetting and in excluding a low septal atrial tachycardia. (AmJCardiol1993,72:1299-1273) trioventricular nodal reentrant tachycatdia (AVNRT) A is 1 of the most common causes of supraventricular tachycardia.’ AVNRT remains a diagnosis of exclusion, and the differentiation of AVNRT from other forms of tachycardia, particularly low atrial tachycardia, can be difficult. The effect of programmed ventricular premature depolarizations during tachycardia has been shown to be critical in helping to establish diagnosis.2 Ventricular premature depolarizations inserted during AVERT, which either terminate the tachycardia without retrograde atrial activation or result in delay of the succeeding atrial impulse, exclude the diagnosis of atria1 tachycardia. Furthermore, a ventricular premature depolarization that advances the tachycardia without change in the atrial activation sequence strongly suggests AVNRT However, because of the short excitable gap and refractoriness of intervening tissue, ventricular premature depolarizations inserted from the right ventricular apex frequently do not enter the tachycardia circuit in patients with AVNRT. We hypothesized that activation closer to the putative reentrant circuit by stimulation near the His bundle would facilitate access into the circuit. Therefore in this study, we compared stimulation of the right ventricular (RV) apex with that of the RV summit in patients with AVNRT.