New algorithm using only lead aVR for differential diagnosis of wide QRS complex tachycardia

Are Available Electrocardiographic Methods Accurate Enough to Diagnose Ventricular Tachycardia in the Emergency Department?

“…17 Last, the differences in the grade of interobserver correlation between the examiners with and without experience with both methods, as well as the previously mentioned diagnostic performance in comparison with that reported in the original studies, 12,13 may be a sign of the need for a learning curve in the evaluation of ECGs. Taking into account the results of the present and previous studies, [9][10][11][12][13][14][15] there is still no single accurate ECG method with sufficient sensitivity, specificity, and simplicity of application by any examiner regardless of the grade of training and experience, to identify VT in a ECG recording with a WCT from any profile of patient attended in daily clinical practice. Single-lead ECG methods such as aVR-alg and RWPT-cri have shown to be probably easier to remember than classical morphologic criteria, but are not as easy in the moment of application, especially the former.…”

“…After the first classical criteria of Wellens et al, 9 a series of criteria and ECG algorithms have been developed with the aim of facilitating the diagnosis. [10][11][12][13] The most well-known and widespread criteria in daily clinical practice are those of Brugada et al, 10 consisting of a four-step algorithm that analyzes the RS complex in the precordial leads and incorporates atrioventricular (AV) dissociation and the classical morphologic criteria in the V 1 -V 2 and V 6 precordial leads, presenting a sensitivity and specificity of 98.7 and 96.5%, respectively.…”

“…In addition to not considering the classical morphologic criteria, this algorithm does not require the criterion of AV dissociation and it is based on the analysis of a single lead, aVR (initial R wave, r or q wave depth > 40 ms, presence of a notch on the descending limb of a negative onset and predominantly negative QRS complex, and Vi/Vt ≤ 1), presenting a diagnostic accuracy similar to the first algorithm and greater than the Brugada criteria. 12 Based on the principle of the analysis of a single lead, a new criterion was recently introduced, that of the R-wave peak time in the DII lead. 13 Previous studies have described that on the application of the different criteria in daily clinical practice by physicians of different specialties and with different grades of experience, the results differ from those originally published, demonstrating lower diagnostic accuracy, sensitivity, and specificity, as well as a moderate interobserver correlation index.…”

“…Second, in contrast to RWPT-crit, the grade of diagnostic accuracy of aVR-alg depends on the examiner experience, which is probably related to the difficulty in delimiting the beginning and the end of the QRS complex when quantifying Vi and Vt. Third, both the mean accuracy and the accuracy of aVR-alg in experienced examiners were lower than those found in the original publication, as were the values of sensitivity and specificity of both methods, thereby providing more evidence on the discrepancy of the results of the methods applied in vitro or in vivo. 12 Fourth, the misdiagnosis of RWPT-cri may be of greater clinical importance than that of aVR-alg since the former tend to confound VT with SVT contrary to what occurs with the latter algorithm. The fifth result showed a higher sensitivity and lower specificity with aVR-alg compared to RWPTcri in the diagnosis of VT overall and for the groups of observers with and without experience (as well as a higher negative predictive value in the hands of experienced examiners).…”

Wide QRS Complex Tachycardia in a Young Healthy Man

“…Brugada 2) emphasized that the absence of an RS complex in all precordial leads or RS interval of more than 100 msec if an RS complex is present is suggestive of VT. Recently, Vereckei 3) proposed that careful observation of lead aVR is useful in diagnosis of wide QRS complex tachycardia. The presence of an initial dominant R wave or an initial r or q wave > 40 msec is suggestive of VT.…”