Objectives To distinguish left ventricular outflow tract (LVOT) from right ventricular outflow tract (RVOT) origin in idiopathic premature ventricular contractions or ventricular tachycardia (PVCs/VT) patients with transitional lead at V3 is still a challenge. We sought to develop a new electrocardiography (ECG) algorithm for distinguishing LVOT from RVOT origin in patients with idiopathic outflow tract PVCs/VT with precordial transitional lead at V3.
Methods We analysed the surface ECG characteristics in a retrospective cohort of idiopathic PVCs/VT patients with transitional lead at V3 who underwent successful radiofrequency catheter ablation and developed a new surface ECG algorithm, then validated it in a prospective cohort.
Results A total of 82 consecutive patients (47 ± 17years, 39% male) underwent radiofrequency catheter ablation of idiopathic outflow tract PVCs/VT between January 2006 and August 2010. Among them, 31 patients (38%) with transitional lead at V3 constituted the retrospective cohort. Based on the areas under the receiver operating characteristic curves, R-wave deflection interval in lead V3 > 80 ms and R-wave amplitude index in lead V1 > 0.30 were selected to develop the new surface ECG algorithm. It correctly identified the origin sites of eleven from 12 patients in the prospective cohort, yielding the accuracy of 91.7%.
Conclusions We presented a new simple surface ECG algorithm, R-wave deflection interval in lead V3 > 80 ms combining with R-wave amplitude index in lead V1 > 0.30 which can reliably distinguish LVOT from RVOT origin in idiopathic outflow tract PVCs/VT in patients with transitional lead at V3.