Surgical VT Ablation
The procedural flowchart and the follow-up results of all 6 patients were summarized in Figure 3. And the 12-lead electrocardiograms of VTs were displayed in Figure 4. Among the 6 patients, three were accessed with limited left thoracotomy and other three with median sternotomy. Notably, previous epicardial RF lesions could hardly be visualized on the cardiac surface in patients with history of epicardial ablation. Voltage mapping, VT induction and activation mapping were performed sequentially before ablation. Clinical VTs could be induced in all patients at baseline in the procedure. With support from anesthesiologists, VTs were hemodynamically tolerated in all patients to allow activation mapping. All the VT locations were shown in Table 2. VTs could be terminated during ablation but easily reinduced in all patients. LVZs and late potentials or fragmented electrograms were targeted and ablated if found (Supplementary Figure 1). After surgical ablation, all the RF lesions were visible.