The V 1 -V 3 transition index as a novel electrocardiographic criterion for differentiating left from right ventricular outflow tract ventricular arrhythmias

The aim of this study was to develop a new electrocardiographic criterion for differentiating the origin of outflow tract ventricular arrhythmias (OT-VAs) with precordial transition in lead V . A total of 147 consecutive patients with OT-VAs displaying precordial transition in lead V who underwent successful catheter ablation in the right ventricular outflow tract (RVOT) (n = 118) or left ventricular outflow tract (LVOT) (n = 29) were included in this study. The V -V transition index was defined as the sum of S-wave amplitude in lead V and V during premature ventricular contractions (PVCs) divided by the S-wave amplitude during sinus rhythm (SR), respectively, minus the sum of R-wave amplitude in lead V , V , and V during PVCs divided by the R-wave amplitude during SR, respectively, i.e., [(S /S )V + (S /S )V ] - [(R /R ) V + (R /R )V + (R /R )V ]. The V -V transition index was significantly higher for RVOT origins than for LVOT origins (1.25 ± 2.48 vs. - 3.94 ± 3.11; P - 1.60 predicted a RVOT origin with a 93% sensitivity and 86% specificity. With respect to AUC and accuracy, the V -V transition index was superior to any previously proposed ECG indices for differentiating left from right OT-VAs. In 37 prospective cases, the new index was able to predict the site of a RVOT origin with 95% accuracy (35 of 37 cases). The V -V transition index is a useful novel ECG criterion for distinguishing left from right OT-VAs with precordial transition in lead V .