3.3. Procedural Outcomes
The number of VT morphologies documented prior to ablation, which were considered clinical VTs, was 1 (IQR, 1 – 1; range, 1 – 5; total 83) (Table 1), and the number of VT morphologies documented during the procedure was 2 (IQR, 1 – 2; range, 0 – 10; total 126) (clinical VT was 1 [IQR, 1 – 1; range, 0 – 5; total 66], and non-clinical VT was 1 [IQR, 0 – 1; range, 0 – 9; total 60].) (Table 2).
Among the 83 clinical VTs, 19 (23%) persisted incessantly at the beginning of the ablation, 47 (57%) were induced during the procedure, and 17 (20%) were not induced during the procedure (Supplementary Table 1.). Among the 66 clinical VTs, which were documented during the procedure, an adequate activation map could be acquired in 24 VTs (36%). The critical isthmus could be identified in 35 clinical VTs (53%); for 26 VTs non-inducibility after ablation could be achieved, and 9 VTs could not be eliminated because the isthmus was deep (7 VTs) or a coronary artery was nearby (2 VTs).
Table 3 shows the ablation data per patient. All clinical VT isthmuses were identified and ablated, and those VTs could not be induced thereafter in 18 patients (28%, Group A); 12 patients (19%) were found by the presence of MDPs and VT termination during the RF ablation, and 6 patients (9%) were found by MESs. On the other hand, all or some clinical VT isthmuses could not be identified or were identified and ablated but remained inducibility in 46 patients (72%, Group B). Among them, 8 patients (13%) underwent ablation after identifying the clinical VT isthmus, but the ablation failed because the isthmus was deep (6 patients) or a coronary artery was nearby (2 patients). In 4 patients (6%), some but not all clinical VT isthmuses were ablated, and in 2 patients (3%) only a nonclinical VT isthmus ablation was performed. Further, thirty patients (47%) underwent only a substrate ablation because no VT isthmuses could be identified.