Epicardial Mapping from Venous Catheter Measurements, Body Surface Potential Maps, and an Electrocardiographic Inverse Solution

1
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
2
Combining Information Sources
3
Venous Catheter Based Mapping
4
Statistical Estimation
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Estimated Activation Maps

• Training set composition
• Lead selection

6
Augmented Inverse Problem
Torso geometry

Body-Surface Potentials

Sparse Epicardial Potentials

Inverse Solution
Epicardial Map
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Subtraction Approach
Known
Unknown
1) Subtract known epicardial potentials
2) Solve reduced inverse problem
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Epicardial Estimation
. . .
t1
t2 ..
.tN
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Combined Estimation
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Bayesian Approach
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Hybrid Approach
Estimate
(m,s)
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Tank/Heart Geometry
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Test Lead Sets
Anterior
42 leads
21 leads
10 leads
Posterior
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Simulation Study

• 490 lead measured sock data
• Surrogate catheter potentials
• 42 sites
• Gaussian noise
• Torso potentials
• Calculated noise-free using forward model
• Gaussian noise

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Leave-One-Experiment Out Protocol
Training Data
Test Data
LV Paced Beats
Dec 18, 2000
Mixed Paced Beats
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LV Pacing (LV-23 ms)
Orig
Subt
MAP
Est Epi
Est All
Hybrid MAP
31 LV-MEpiP-23 ms
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LV Pacing (LV-38 ms)
Orig
Subt
MAP
Est Epi
Est All
Hybrid MAP
31 LV-MEpiP-38 ms
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LV Pacing (LV-47 ms)
31 LV-MEpiP-47 ms
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LV Pacing (Mixed-23 ms)
31 LV-RV-MEpiP-23 ms
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LV Pacing (Mixed-38 ms)
31 LV-RV-MEpiP-38 ms
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LV Pacing (Mixed-47 ms)
31 LV-RV-MEpiP-47 ms
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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
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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
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Estimation Findings

• Estimation alone noisy, unstable results
• Estimation inverse smoothing improves stability

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Inverse Solution Findings

• All solutions better than simple Tikhonov
• MAP usually improved with addition of catheter
  measurements (Hybrid MAP)

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Role of Statistics (Training)

• Generally helps
• But can add artifacts, e.g., spurious
  breakthroughs or wavefronts
• Torso potentials can reduce artifacts

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Conclusion
More (bigger) is better..