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A reliability analysis of cardiac repolarization time markers
S Scacchi1, P Colli Franzone, L F Pavarino
1Dipartimento di Matematica, Università di Milano, Via Saldini 50, 20133 Milano, Italy. simone.scacchi@unimi.it
Mathematical Biosciences
|March 31, 2009
Summary
This study validates extracellular markers for cardiac repolarization time, finding a good global match with transmembrane action potentials but highlighting potential local discrepancies. These findings impact the accuracy of activation-recovery intervals in estimating action potential durations.
Area of Science:
- Computational electrophysiology
- Cardiac electrophysiology modeling
- Biophysics
Background:
- Limited studies exist on the reliability of extracellular markers for cardiac repolarization time.
- Classical markers like RT(eg) are used but their accuracy needs further investigation.
- Previous research established a foundation with one-dimensional simulations.
Purpose of the Study:
- To extensively evaluate extracellular markers of cardiac repolarization time using 3D simulations.
- To compare classical (RT(eg)) and novel (RT90(eg)) extracellular markers against transmembrane action potential (TAP) gold standards.
- To assess the accuracy of activation-recovery intervals (ARI) in reflecting action potential durations (APD).
Main Methods:
- Utilized a 3D bidomain-Luo-Rudy phase I simulation system.
- Incorporated rotational fiber anisotropy and heterogeneous transmural membrane properties.
- Compared extracellular markers (RT(eg), RT90(eg)) with transmembrane markers (RT(tap), RT90(tap)).
Main Results:
- Demonstrated a good global correlation (r > 0.92) and small discrepancy (<1.6%) between extracellular and transmembrane repolarization markers.
- Identified significant local discrepancies in regions with abrupt or uniform repolarization front changes.
- Showed that ARI may inaccurately estimate APD distributions due to these local variations.
Conclusions:
- Extracellular repolarization markers offer a reasonably accurate global estimation of transmembrane repolarization.
- Local variations in repolarization dynamics can lead to significant discrepancies between extracellular and transmembrane measurements.
- The spatial distribution of ARI may not reliably represent APD, particularly in complex cardiac tissue geometries.
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