Simple electrocardiographic criteria for rapid identification of wide QRS complex tachycardia: The new limb lead algorithm

Background The electrocardiogram (ECG) is essential for the differential diagnosis of wide QRS complex tachycardia (WCT). Objective The purpose of this study was to evaluate the diagnostic value of a novel ECG algorithm on the basis of the morphological characteristics of the QRS on the limb leads. Methods The limb lead algorithm (LLA) was evaluated by analyzing 528 monomorphic WCTs with electrophysiology-confirmed diagnoses. In the LLA, ventricular tachycardia (VT) is diagnosed in the presence of at least 1 of the following: (1) monophasic R wave in lead aVR; (2) predominantly negative QRS in leads I, II, and III; and (3) opposing QRS complex in the limb leads: concordant monophasic QRS in all 3 inferior leads and concordant monophasic QRS in 2 or 3 of the remaining limb leads with a polarity opposite to that of the inferior leads. The diagnostic performance of the LLA was compared with that of the Brugada, Vereckei, and R-wave peak time (RWPT) algorithms. Results Of 528 WCT cases, 397 were VT and 131 supraventricular tachycardia. The interobserver agreement for the LLA was excellent (κ = 0.98), better than that for the other algorithms. The overall accuracy of the LLA (88.1%) was similar to that of Brugada (85.4%) and Vereckei (88.1%) algorithms but was higher than that of the RWPT algorithm (70.8%). The LLA had a lower sensitivity (87.2%) than did Brugada (94.0%) and Vereckei (92.4%) algorithms, but not the RWPT algorithm (67.8%). Furthermore, the LLA showed a higher specificity (90.8%) than did Brugada (59.5%), Vereckei (76.3%), and RWPT (80.2%) algorithms. Conclusion The LLA is a simple yet accurate method to diagnose VT when approaching WCTs on the ECG. The electrocardiogram (ECG) is essential for the differential diagnosis of wide QRS complex tachycardia (WCT). The purpose of this study was to evaluate the diagnostic value of a novel ECG algorithm on the basis of the morphological characteristics of the QRS on the limb leads. The limb lead algorithm (LLA) was evaluated by analyzing 528 monomorphic WCTs with electrophysiology-confirmed diagnoses. In the LLA, ventricular tachycardia (VT) is diagnosed in the presence of at least 1 of the following: (1) monophasic R wave in lead aVR; (2) predominantly negative QRS in leads I, II, and III; and (3) opposing QRS complex in the limb leads: concordant monophasic QRS in all 3 inferior leads and concordant monophasic QRS in 2 or 3 of the remaining limb leads with a polarity opposite to that of the inferior leads. The diagnostic performance of the LLA was compared with that of the Brugada, Vereckei, and R-wave peak time (RWPT) algorithms. Of 528 WCT cases, 397 were VT and 131 supraventricular tachycardia. The interobserver agreement for the LLA was excellent (κ = 0.98), better than that for the other algorithms. The overall accuracy of the LLA (88.1%) was similar to that of Brugada (85.4%) and Vereckei (88.1%) algorithms but was higher than that of the RWPT algorithm (70.8%). The LLA had a lower sensitivity (87.2%) than did Brugada (94.0%) and Vereckei (92.4%) algorithms, but not the RWPT algorithm (67.8%). Furthermore, the LLA showed a higher specificity (90.8%) than did Brugada (59.5%), Vereckei (76.3%), and RWPT (80.2%) algorithms. The LLA is a simple yet accurate method to diagnose VT when approaching WCTs on the ECG.