Article Text
Abstract
Objectives Until now, no ventricular arrhythmias QRS axis dominated ECG algorithms was used to differentiate ventricular tachycardia or premature ventricular complexes (VT/PVCs) originating from the free wall or septum in the RVOT. In this study, we designed new ECG criteria and investigated the sensitivity and specificity of them in practice.
Methods Consecutive 120 patients with left bundle branch block morphology and precordial transition lead ≥ V4 were successfully underwent mapping and ablation. They were rerolled into the septum group (n = 95) and the free wall group (n = 25) according to VT/PVCs origin. We analysed the ECG pattern with following criteria. 1) QRS axis > 89°; 2) R wave amplitude in lead III > II, and 3) A2III score included QRS axis > 84.5° (score = 1), lead III QRS duration > 154.5 ms (score = 1) and AVL QRS duration > 156.5 ms (score = 1).
Results Retrospective analysis showed that VT/PVC axis > 89° or R wave amplitude in lead III > II predict VT/PVC originating from the septum with 100.00% sensitivity, 93.94% specificity, and 97.78% positive prediction value. A2III score ≥ 2 predicts VT/PVCs originating from the free wall in the RVOT with 80.00% sensitivity, 87.50% specificity and 84.09% positive predictor value. The new algorithms predict VT/PVCs originating from the free wall in the RVOT with the overall sensitivity, specificity, and positive predictor value were 81.48%, 91.30% and 88.76%. Prospective analysis in 20 patients showed that VT/PVCs originating from the free wall in the RVOT with the overall sensitivity, specificity, and positive predictor value were 90%, 89.74% and 95%.
Conclusions VT/PVC axis > 89°, R wave amplitude in lead III > II and A2III score < 2 with very high sensitivity, specificity and positive prediction value for prediction VT/PVCs originating from the septum origin in the RVOT. A2III score ≥ 2 predicts VT/PVCs originating from the free wall in the RVOT.