Variability of the VA interval at tachycardia induction: a simple method to differentiate orthodromic reciprocating tachycardia from atypical atrioventricular nodal reentrant tachycardia

Spontaneous Variation of Ventriculo-Atrial Interval after Tachycardia Induction: Determinants and Usefulness in the Diagnosis of Supraventricular Tachycardias with Long Ventriculoatrial Interval

“…Such was the study protocol, designed to obtain more comparable and homogeneous results. On the other hand, our results show some discrepancies with other recent series [ 3 ], probably due to the different methodology used in the timing of VA intervals measurements. Finally, although the variable we propose does not offer an absolute diagnostic accuracy (i.e., its sensitivity is not greater than 50%), we consider that our findings provide information that could be applied during routine clinical practice.…”

“…In our opinion, the discrepancies between the two studies are a consequence of differences in the method and timing of VA interval measurements, and of the sample size, with more ORTs analyzed in our series. According to our data, the cuttoff proposed by Hadid et al [ 3 ] is not specific enough, since 6% of all ORTs present a Dif-VA >10 ms in the 10 beats following induction ( Figure 3 ). The greater number of ORTs analysed and the greater number of VA interval measurements performed by our group (10 versus an average of 2), as well as the unpredictable nature of VA interval variation [ 21 ] (in 10% of ORTs the Dif-VA increases from induction to one minute later) justifies this difference.…”

“…Previous studies have shown a certain degree of spatial heterogeneity of retrograde atrial activation during AVNRT [ 17 , 18 ] and of conduction times (determined by the duration of the VA interval), especially after induction or when sudden changes in heart rate have occurred [ 19 , 20 ]. Recently, it has been proposed that a maximum VA interval variation of 10 ms or more immediately after tachycardia induction has a diagnostic accuracy of 100% for AVRNT, ruling out ORT [ 3 ]. In our opinion, the discrepancies between the two studies are a consequence of differences in the method and timing of VA interval measurements, and of the sample size, with more ORTs analyzed in our series.…”

“…Then, the exact mechanism of the tachycardia (atypical AVNRT or ORT) was determined according to electrophysiologic criteria [ 2 , 10 , 11 , 12 ] and results of catheter ablation. The classification of AVNRTs was made following the criteria proposed by Kastritsis et al [ 6 ] because of its clarity, simplicity and wide acceptance [ 3 , 13 ].…”

“…Since the retrograde arm of atrioventricular nodal reentrant tachycardias (AVNRTs) and orthodromic reentrant tachycardias through an accessory pathway (ORTs) have different electrophysiological properties, the analysis of the behavior of VA intervals during induced tachycardia could provide diagnostic information. It has recently been proposed that VA interval variation in tachycardia may be useful to differentiate atypical AVNRTs and orthodromic reciprocating tachycardias [ 3 ]. We present the results of a prospective series in which we analysed the determinants, time course, and diagnostic accuracy of spontaneous VA interval variation in a prospective, non-selective series of patients with narrow QRS tachycardias and prolonged VA.…”