Differentiating the origin of outflow tract premature ventricular complexes using the QRS-right ventricular apex interval

Background For localization of outflow tract Premature ventricular complexes (PVCs) many ECG criteria have been proposed, however in some cases it is difficult to accurately localize the origin of PVCs using the surface ECG. Objective This study aims to study the relation between QRS-right ventricular apex interval and the origin of the outflow tract PVCs. Patients and Methods The study included 30 patients (27 female, age 37.20 ± 7.87, RVOT origin 18) referred for PVCs ablation and we measured the interval from the onset of the earliest QRS complex of premature ventricular contractions (PVCs) to the distal right ventricular apical signal, (the QRS-RVA interval) and correlated this interval with origin of outflow tract PVCs as identified by the successful ablation during the procedure. Results Compared to PVCs originating from RVOT, the QRS-RVA interval was significantly longer in PVCs originating from LVOT (67.33±7.56 for LVOT PVCs vs. 37.11±4.34 for RVOT PVCs, p < 0.001). Receiver operating characteristic (ROC) analysis showed that a QRSRVA interval ≥47 ms has a sensitivity, specificity, positive and negative predictive values of 100%, 100%, 100%, 100% respectively, for prediction of an LVOT origin of PVCs Conclusion The QRS-RVA interval is a simple and accurate criterion for differentiating the origin of outflow tract arrhythmia during electrophysiology study, A QRS-RVA interval ≥47 ms suggests an LVOT origin of PVCs.