Key result
2D surface calculations overestimate true 3D conduction velocity by ~23%, worsening at lower resolutions.
Why the study?
Electroanatomical maps using automated conduction velocity algorithms rely on 2D mapping tools, but their accuracy compared to 3D vectors and the impact of mapping resolution remain unclear.
Absolute Event Rate: 527.7% vs 429.2%
p-value: p=<0.01
2D LAT-based conduction velocity calculations significantly overestimate true ventricular conduction velocity, especially at lower mapping resolutions, indicating a need for 3D electric field-based mapping approaches.
2D CV mapping may overestimate true ventricular conduction velocity; leaves open whether 3D electric field-based approaches improve clinical accuracy.
AIMS: Electroanatomical maps using automated conduction velocity (CV) algorithms are now being calculated using two-dimensional (2D) mapping tools. We studied the accuracy of mapping surface 2D CV, compared to the three-dimensional (3D) vectors, and the influence of mapping resolution in non-scarred animal and human heart models. METHODS AND RESULTS: Two models were used: a healthy porcine Langendorff model with transmural needle electrodes and a computer stimulation model of the ventricles built from an MRI-segmented, excised human heart. Local activation times (LATs) within the 3D volume of the mesh were used to calculate true 3D CVs (direction and velocity) for different pixel resolutions ranging between 500 μm and 4 mm (3D CVs). CV was also calculated for endocardial surface-only LATs (2D CV). In the experimental model, surface (2D) CV was faster on the epicardium (0.509 m/s) compared to the endocardium (0.262 m/s). In stimulation models, 2D CV significantly exceeded 3D CVs across all mapping resolutions and increased as resolution decreased. Three-dimensional and 2D left ventricle CV at 500 μm resolution increased from 429.2 ± 189.3 to 527.7 ± 253.8 mm/s (P < 0.01), respectively, with modest correlation (R = 0.64). Decreasing the resolution to 4 mm significantly increased 2D CV and weakened the correlation (R = 0.46). The majority of CV vectors were not parallel (<30°) to the mapping surface providing a potential mechanistic explanation for erroneous LAT-based CV over-estimation. CONCLUSION: Ventricular CV is overestimated when using 2D LAT-based CV calculation of the mapping surface and significantly compounded by mapping resolution. Three-dimensional electric field-based approaches are needed in mapping true CV on mapping surfaces.
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Padilla et al. (2023) studied Cardiac mapping (healthy porcine and human heart models). 2D mapping surface conduction velocity (CV) calculation vs. 3D volume conduction velocity calculation was evaluated on Accuracy of mapping surface 2D CV compared to 3D vectors (p=<0.01). Two-dimensional surface-based conduction velocity calculations significantly overestimated true 3D conduction velocity (527.7 vs 429.2 mm/s at 500 μm resolution, P<0.01), worsening at lower resolutions.
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