Clinical significance of conduction velocity orientation vectors on cardiac mapping surfaces

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main source(s): This work was supported by the Lefoulon Delalande Foundation OBJECTIVE Electroanatomical maps using automated conduction velocity (CV) algorithms are now being calculated 2D mapping tools. The basis substrate-based functional assessment is to detect slow zones or CV which isochronal late activation (ILAM) commonly performed. We studied accuracy surface CV, compared 3D vectors, and influence resolution in non-scarred animal human heart models. Methods Two models were used: a healthy porcine Langendorff model with transmural needle electrodes computer stimulation ventricles built from an MRI-segmented, excised heart. Local times (LAT) within volume mesh used calculate true CVs (direction velocity) for different pixel resolutions ranging between 500 mm – 4 (3D CVs). also endocardial surface-only LATs (2D CV). Results In experimental model, (2D) faster on epicardium (0.509 m/s) endocardium (0.262 m/s, Figure 1). models, significantly exceeded across all increased as decreased (Figure 2). left ventricle at 500mm 429.2±189.3 mm/s 527.7±253.8 (P<0.01), respectively modest correlation (R=0.64). Decreasing 4mm weakened (R=0.46). majority vectors not parallel (<30°) providing potential mechanistic explanation erroneous LAT-based over-estimation. Conclusion Ventricular overestimated when calculation compounded resolution. These findings have implications current methodology substrate ILAM assessment.