Matrix mapping of different idiopathic right ventricular outflow arrhythmias.

OBJECTIVE To explore the characteristics of optimal ablation site and its surrounding tissue in terms of unipolar and bipolar voltage mapping in idiopathic arrythmias from right ventricular outflow tract (RVOT) to understand if there is any difference between the two arrhythmias in matrix. METHOD A total of 40 patients with idiopathic arrhythmias originated from RVOT (28 PVCs/12 VT) were enrolled in the study group. The control group consisted of five patients with supraventricular tachycardia (SVT). Before ablation, the CARTO system was applied to establish a detailed three-dimensional electroanatomic voltage map (EVM) of RVOT during the sinus rhythm. RESULTS A band-like LVA of similar size was observed under the pulmonary valve on not only the bipolar map, but also unipolar map, for every patient. Both unipolar and bipolar voltage values in areas within 5 mm were significantly different from those in other areas above ablation targets, whereas similar differences were observed only in unipolar voltage values below the optimal ablation site for either of the two arrhythmias. Significant difference was present between VT group and VPCs group in voltage values for every area including target site. In terms of the overall LVA areas and the scar areas displayed on the unipolar and bipolar voltage maps, there was a significant difference between the unipolar value and bipolar value for the LVA areas and the scar areas in the VT or PVC group (P<0.05). CONCLUSIONS There was focal micro-scarring around the optimal ablation site. The ectopic focus is probably located in mid- or epi-myocardium. The distributions of majority of optimal ablation sites were regular especially at the noteworthy border of the band-like LVA on bipolar voltage map, or in the band-like LVA on unipolar voltage map.