Electrophysiological characteristics of earliest activation in ventricular arrythmias originating from right ventricular outflow tract, correlation with voltage mapping

Objective This study was aimed to evaluate electrophysiological characteristics of earliest activation in ventricular arrythmias originating from right ventricular outflow tract (RVOT) tachycardia(ventricular tachycardia/premature ventricular contraction, VT/PVC) by noncontact and contact voltage mapping. Methods Fifty-one patients suffered from RVOT-PVC/VT were enrolled in this study(VT group, 23 patients, non-sustained VT; PVC group, 28 patients). Ensite Array noncontact mapping(St Jude, USA)was applied to find out the earliest activation(EA) and break out(BO)of PVC/VT, then contact voltage mapping of RVOT was created during sinus rhythm.The distribution of ablation targets were analyzed accordance with voltage mapping. Results The total success rate was 94.1% in all population(48/51). The success rate in VT group(95.7%, 22/23)compared with that in PVC group(92.9%, 26/28). The average target voltage of VT group under sinus rhythm was significantly lower than that in PVC group [(1.0±0.9) mV vs. (1.8±1.6) mV, P=0.045]. There was no significant difference in the average target voltage of VT/PVC during clinical arrhythmias[(2.4±2.0) mV vs. (2.7±2.1) mV, P=0.845], neither was the target duration time advanced to VT/PVC QRS [(40.8±4.0) ms vs.(39.2±3.6) ms, P=0.180]. VT group had more preference originating from low-voltage areas than PVC group(82.6% vs.50%, P=0.031). The first 10 ms dV/dt in VT group was inferior to PVC group [(0.9±0.7)vs.(1.7±1.1), P=0.010]. The EA-BO time of in VT group was significantly longer than PVC group [(14.3±6.0) ms vs.(10.2±4.3) ms, P=0.044], and more agressive ablation needed(11/23 vs.6/28, P=0.034). Conclusions VT group had lower initiate dv/dt and longer EA-BO distance, and needsed more aggressive ablations.The majority originating sites of idiopathic RVOT arrhythmias were located in low-voltage zone.VT group showed preferences.Voltage mapping may play an important role inablation of RVOT-concerned arrhythmias. Key words: Right ventricular outflow tract; Premature ventricular contraction; Ventricular tachycardia; Noncontact mapping; Voltage mapping