Application of a new algorithm in the differential diagnosis of wide QRS complex tachycardia

Aims The Brugada criteria proposed to distinguish between regular, monomorphic wide QRS complex tachycardias (WCT) caused by supraventricular (SVT) and ventricular tachycardia (VT) have been reported to have a better sensitivity and specificity than the traditional criteria. By incorporating two new criteria, a new, simplified algorithm was devised and compared with the Brugada criteria. Methods and results A total of 453 WCTs (331 VTs, 105 SVTs, 17 pre-excited tachycardias) from 287 consecutive patients with a proven electrophysiological (EP) diagnosis were prospectively analysed by two of the authors blinded to the EP diagnosis. The following criteria were analysed: (i) presence of AV dissociation; (ii) presence of an initial R wave in lead aVR; (iii) whether the morphology of the WCT correspond to bundle branch or fascicular block; (iv) estimation of initial (v i) and terminal (v t) ventricular activation velocity ratio (v i/v t) by measuring the voltage change on the ECG tracing during the initial 40 ms (v i) and the terminal 40 ms (v t) of the same bi- or multiphasic QRS complex. A v i/v t >1 was suggestive of SVT and a v i/v t ≤1 of VT. An initial R wave in lead aVR suggested VT. The overall test accuracy of the new algorithm was superior (P = 0.006) to that of the Brugada criteria. The new algorithm had a greater sensitivity (P < 0.001) and (−) predictive value (NPV) for VT diagnosis, and specificity (P = 0.0471) and (+) predictive value (PPV) for SVT diagnosis than those of the Brugada criteria [both NPV for VT diagnosis and PPV for SVT diagnosis were: 83.5% (95% confidence interval = CI 75.9-91.1%) for the new vs. 65.2% (95% CI 56.5-73.9%) for the Brugada algorithms]. Conclusion The new algorithm is a highly accurate tool for correctly diagnosing the cause of WCT ECGs.