Value of the electrocardiographic signs in differential diagnosis of atrioventricular nodal reentrant tachycardia

We read with great interest the article: ‘Value of the aVR lead in differential diagnosis of atrioventricular nodal reentrant tachycardia’ by Haghjoo et al.¹ in a recent issue of the journal.

We would like to comment that the specificity of an electrocardiographic sign guarantees that in the presence of this sign, the likelihood of the disease in question is high. On the contrary, the sensitivity of a particular sign guarantees that in the absence of this sign, the likelihood of not having the disease in question is high.

Most electrocardiographic signs as we know have high specificity and low sensitivity. This means that their presence appears to be more useful than their absence.

Haghjoo et al. reported the value of the aVR lead in differential diagnosis of atrioventricular nodal reentrant tachycardia (AVNRT). They reported that a sensitivity of 67% and a specificity of 90% for the pseudo-r′-wave in aVR.

We previously reported the utility of the aVL lead in the electrocardiographic diagnosis of AVNRT.²

In our series, the sensitivity for the notch in aVL was 48.6% and its specificity was 92.6%. The specificity we found was similar to that of the classic signs (pseudo-S-wave in inferior leads 93%, pseudo-R-wave V1 91%). The area under the receiver operating characteristic curve was calculated between the notch in aVL and the classic signs, so we concluded that our sign was at least similar to the classic signs.

The specificity of the pseudo-r′ in aVR and the terminal notching in aVL were identical in Majid's series. Although they did not make any statistical test to compare the signs, they concluded that pseudo-r′ in aVR was more accurate than standard criteria. This conclusion is not entirely correct. The pseudo-r′ in aVR show a better positive predictive value than terminal notching in aVL but it is dependent on prevalence of the sign (51.3% aVL notch in our series vs. 41% in Majid Haghjoo's article). We believe that pseudo-r′-wave in aVR and terminal notching in aVL are useful tools for the differential diagnosis between AVNRT and atrioventricular reentrant tachycardia but we cannot be sure that these signs are better than the classic signs yet. More data are necessary to answer this question. Meanwhile, we recommend taking advantage of all electrocardiographic criteria available to make the diagnosis of AVNRT.

Conflict of interest: none declared.

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