Predicting Of The Origin And Catheter Ablation Of Idiopathic Outflow Tract Premature Ventricular Complex With V3Transition

Objective: There has still been controversy over locating the origin point oftransition at lead V3in patients with idiopathic premature ventricular contraction(PVC) from the outflow tract. This study intended to summarize the ECGcharacteristics and ablation strategies at different origin points of R/S transitions atlead V3in patients with PVC.Methods:34idiopathic out-flow-tract PVC patients with transition at lead V3were continuously selected and, according to the final ablation sites, divided into aright-ventricular-outflow-tract (RVOT) group of22patients (65%), aleft-ventricular-outflow-tract (LVOT) group of8patients (23%) and anepicardial-outflow-tract group of4patients (12%). leads (V1-V3) of patients in thethree groups were measured for r-or R-wave duration of lead V1during sinusarrhythmia (SR), R-wave amplitude ratio and V2and V3transition ratios during PVC,and R-and S-wave amplitudes during PC and SR respectively. ECG characteristicsof the three groups were compared.Results: V2transition ratio at LVOT was greater than that at RVOT (P<0.05). Iftransition in each lead during PVC was later than that during SR, LVOT origin shouldnot be considered; R-wave duration of lead V1at LVOT was wider than that at RVOT(P<0.05); R-wave amplitude of lead V2at LVOT was higher than that at RVOT(P<0.05).Conclusions: For out-flow PVC patients with transition at lead V3, if transitionin precordial lead was later than that during SR, one should be considered of RVOTorigin and the mapping and ablation should be first performed at RVOT; if ablation atRVOT failed, then the mapping and ablation should be first performed at LVOTinstead. If an ideal target was not mapped neither at RVOT nor at LVOT, epicardialablation in the coronary sinus should be performed on patients with unfavorableoutcome after ablation in order to achieve the best effects.