International Circulation:  Could you please talk about the strategy of Mapping of right ventricular outflow tract ventricular tachycardia?

　　《国际循环》：您对于右室流出道所致的心动过速进行标测有何观点?

　　Roberto De Ponti: This can be a very particular and peculiar tachycardia. In some cases this type of tachycardia can be sustained clinically， while in others you are in trouble when you have to induce this kind of tachycardia during the electrophysiological study. When you have a sustained form of tachycardia during the EP study， you can do activation mapping by using the 3D electroanatomical system and you are able to reconstruct the activation in the right ventricular outflow tract. Then you can identify the early site of activation and deliver radiofrequency energy there. In the vast majority， or at least in 70-80% of these cases， you are very lucky to obtain and achieve long-term success with relatively few radiofrequency ablation applications. When you don’t have such a pattern of the arrhythmia and have only single or multiple PVCs coming from this site， our approach is to electroanatomically reconstruct the right ventricle outflow tract during sinus rhythm. Then， we go acquire no more than 10-15 beats of this tachycardia using the 10-beat buffer option. Based on these beats we are able to identify the early site of activation based on bipolar and unipolar signal analysis. In the vast majority of these cases， we are able as well to ablate this arrhythmia successfully， even if we do not observe its sustained form during the electrophysiologic procedure. In my opinion， pace-mapping for this tachycardia is definitely less reliable.