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Epicardial Mapping from Venous Catheter Measurements, Body Surface Potential Maps, and an Electrocardiographic Inverse Solution. Robert S. MacLeod, Yesim Serinagaoglu*, Bulent Yilmaz, and Dana H. Brooks*. NEH Cardiovascular Research and Training Institute (CVRTI), U of Utah
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Epicardial Mapping from Venous Catheter Measurements, Body Surface Potential Maps, and an Electrocardiographic Inverse Solution Robert S. MacLeod, Yesim Serinagaoglu*, Bulent Yilmaz, and Dana H. Brooks* NEH Cardiovascular Research and Training Institute (CVRTI), U of Utah *Communications and Digital Signal Processing (CDSP), Northeastern U
Forward Inverse Combining Information Sources
Training Data Covariance Matrix Sparse Test Data Estimate = Estimation Matrix * Statistical Estimation
Original Mixed RV-only LV-only Estimated Activation Maps • Training set composition • Lead selection
Forward Inverse Augmented Inverse Problem Torso geometry + Body-Surface Potentials + Sparse Epicardial Potentials + Inverse Solution Epicardial Map
Inverse(Tikhonov) Subtraction Approach Unknown Known 1) Subtract known epicardial potentials 2) Solve reduced inverse problem
Estimation Epicardial Estimation . . . t1 t2 ….. ….tN
Estimation Combined Estimation
(m,s) Inverse(MAP) Bayesian Approach
Inverse(MAP) Hybrid Approach Estimate (m,s)
Test Lead Sets Anterior 42 leads 21 leads 10 leads Posterior
Simulation Study • 490 lead measured sock data • Surrogate catheter potentials • 42 sites • + Gaussian noise • Torso potentials • Calculated noise-free using forward model • + Gaussian noise
Dec 13, 2000 Dec 13, 2000 Leave-One-Experiment Out Protocol Training Data Test Data LV Paced Beats Dec 18, 2000 Mixed Paced Beats
LV Pacing (LV-23 ms) Orig Subt MAP Est Epi Est All Hybrid MAP 31: LV-MEpiP-23 ms
LV Pacing (LV-38 ms) Orig Subt MAP Est Epi Est All Hybrid MAP 31: LV-MEpiP-38 ms
Orig Subt MAP Est Epi Est All Hybrid MAP LV Pacing (LV-47 ms) 31: LV-MEpiP-47 ms
Orig Subt MAP Est Epi Est All Hybrid MAP LV Pacing (Mixed-23 ms) 31: LV-RV-MEpiP-23 ms
Orig Subt MAP Est Epi Est All Hybrid MAP LV Pacing (Mixed-38 ms) 31: LV-RV-MEpiP-38 ms
Orig Subt MAP Est Epi Est All Hybrid MAP LV Pacing (Mixed-47 ms) 31: LV-RV-MEpiP-47 ms
MAP Estim-Epi Estim-All MAP-Hybrid Subtr Relative Error (31-LV) 1.4 1.2 1 Relative Error 0.8 0.6 0.4 0.2 0 0 10 20 30 40 50 60 70 80 90 100 Time [ms]
MAP Estim-Epi Estim-All MAP-Hybrid Subtr Relative Error (31-Mixed) 1.4 1.2 1 Relative Error 0.8 0.6 0.4 0.2 0 0 10 20 30 40 50 60 70 80 90 100 Time [ms]
Estimation Findings • Estimation alone: noisy, unstable results • Estimation + inverse: smoothing improves stability
Inverse Solution Findings • All solutions better than simple Tikhonov • MAP usually improved with addition of catheter measurements (Hybrid MAP)
Role of Statistics (Training) • Generally helps • But can add artifacts, e.g., spurious breakthroughs or wavefronts • Torso potentials can reduce artifacts
… but not always Conclusion More (bigger) is better…..