Table 3.

Accuracy of VT exit localization achieved by the automated localization system

Case#	Mapped VT	VT Exit/Ablation Site	Localization Error (mm)
			Population-based localization within a segment		Patient-specific site localization
			Observer 1	Observer 2
1	VT1	Basal anterolateral LV	9.3	4.5	3.9
2	VT1	—	—	—	—
	VT2	Inferolateral LV, between the mid and apical thirds	17.0	16.6	8.9
	VT3	Mid inferior septum	11.2	10.7	7.3
4	VT1	Inferolateral segment	*	*	*
5	VT1	—	—	—	—
6	VT1	Basal inferior LV	12.2	6.1	14.4
7	VT1	Aortomitral continuity	12	4.1	4.1
	VT2	Basal inferior	11.2	10.3	16.0
8	VT1	Basal inferior septum	9.2	6.3	2.9
	VT2	Basal inferior septum	*	*	*
9	VT1	Septal basal margin of the scar	*	*	*
	VT2	Septal margin of the scar	6.4	0.0	9.3
12	VT1	Superior lateral margin of the scar	10.2	9.8	10.7
	VT2	Basal septal margin of the scar	10.4	4.7	4.0
13	VT1	Base of the inferior LV septum	6.9	9.5	6.8
	VT2	—	—	—	—
	VT3	—	—	—	—
14	VT1	Mid anterolateral segment	11.2	6.4	12.4
	VT2	Basal anterior wall	9.3	9.0	10.8
	VT3	Right coronary cusp	9.4	5.8	2.7
	VT4	Basal inferoseptal segment	6.9	20.1	13.6
15	VT1	—	—	—	—
	VT2	Lateral scar margin	*	*	*
	VT3	Apical scar margin	9.8	0.0	7.8
16	VT1	—	—	—	—
	VT2	Junction of the inferolateral and Inferoapical segments	8.2	11.1	5.2
	VT3	Inferoseptal apical segment	*	*	*
17	VT1	Anterolateral segment	7.0	7.0	3.8
	VT2	Basal anterolateral segments	11.2	10.8	3.8
	VT3	—	—	—	—
	VT4	—	—	—	—
	VT5	Below the right coronary cusp	†	†	†
	VT6	Apical inferior septum	†	†	†
	VT7	Superior basal septum	7.2	11.9	3.6
18	VT1	Apical anterolateral region	8.2	8.2	8.6
	VT2	Non-sustained	—	—	—
19	VT1	—	—	—	—
	VT2	—	—	—	—
	VT3	—	—	—	—
	VT4	—	—	—	—
	VT5	Basal superior septum,	13.0	9.4	7.0
	VT6	His proximal region	*	*	*
20	VT1	Inferoseptal region	6.5	0.0	7.6
	VT2	Mid posterior scar margin	*	*	*
	VT3	Mid inferoseptal region	*	*	*
21	VT1	Mid anterolateral wall superior to the papillary muscle	6.2	4.8	0.0
	VT2	Mid-apical anterolateral wall inferior to the papillary muscle	6.7	9.6	5.3

The error of VT-exit localization was calculated as Euclidean distance between the estimated VT-exit site and the known VT-exit site. ‘—’ indicates that the VT was not mapped, and an exit site was therefore not identified. The ‘*’ indicates VTs that were terminated within the middle of the scar at sites proximal to the scar exit site (in which cases localization accuracy could not be precisely quantitated because VT was terminated at a mid-diastolic site).

^†Indicates that site of origin/ablation site was only approximately localized.