Retrospective study of the electrophysiological characteristics and criteria of ablation target for ventricular arrhythmia originating from right ventricular outflow tract

Objective The purpose of this study was to analyze the target distribution characteristics, the voltage characteristics, and electrophysiological characteristics of unipolar potential in right ventricular outflow tract(RVOT)ventricular arrhythmias(VA). We expected to optimize the diagnostic criteria of the ablation targets for RVOT VA. Methods One hundred and forty-six consecutive patients with VA originating from RVOT underwent radiofrequency catheter ablation(RFCA)in Zhongshan Hospital from June 2016 to August 2017 were studied.One hundred and fifty-three types of premature ventricular complexes(PVC)and 6 types of ventricular tachycardia(VT)were recorded during the procedure.We recorded 141 successful targets(ST)and 192 failed targets(FT). RVOT was divided into three parts by the detailed three-dimensional voltage mapping using the Carto system prior to the RFCA.The voltage on bipolar electrogram was defined as follows: amplitude 1.5 mV as "normal-voltage zone" . Results One hundred and thirty-four patients with 141 targets were successfully ablated, and 12 patients failed.In the ST group, ablation target was located in normal-voltage zone in 23 patients, in transitional-voltage zone in 95 patients, and low-voltage zone in 23 patients.There was no significant difference of the max slope of the descending limb(MSDL)between ST group and FT group.The local activation preceding time(LAPT)was earlier in ST group than that in FT group [(29.7±4.5)ms vs.(23.0±6.5)ms, P<0.001]. The interval of MSDL(IMSDL)was shorter in ST group than that in FT group [(11.80±10.39)ms vs.(21.64±11.83)ms, P=0.001]. The IMSDL and LAPT were both valuable predictive indexes for ST, whose area under curve(AUC) were 70.7% and 81.1%, respectively.A better predictive value could acquire when IMSDL and LAPT were combined used(AUC 89.3%, sensibility 75.8%, specificity 90.4%). Conclusions Pulmonary subvalves are the sites of RVOT VA.A better predictive value can be acquired when IMSDL and LAPT are combined. Key words: Ventricular premature complexes; Catheter ablation