Noninvasive Cardiac Electrogram Reconstruction via Laplace Equation
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Solution Overview
Problem
Current noninvasive electrophysiological studies of the heart face challenges in accurately reconstructing the heart's electric field due to the invasive nature of existing methods and the neglect of varying electroconductivity coefficients of chest tissues, leading to reduced accuracy in diagnosing cardiac electrophysiological processes.
Innovation Solution
A computational method is employed to reconstruct electrograms from unipolar ECGs recorded on the chest surface, using a model with varying electroconductivity coefficients for different chest tissues, and applying the boundary element method to solve the Cauchy problem for the Laplace equation, with an iterative algorithm and fast multipole method for improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive methods (catheters, probes) are used to obtain electrograms close to the heart surface, then measurement precision of local electric activity is improved, but patient safety and ease of operation deteriorate
Solution Approach 1:
The patent creates a computational copy of the invasive measurement process. Instead of physically placing electrodes on the heart surface, the system uses surface ECG data combined with a computational model (including chest wall geometry and tissue electroconductivity) to generate virtual electrograms that replicate what invasive electrodes would measure, thereby achieving high measurement precision without patient invasion
Solution Approach 2:
The patent replaces the mechanical invasive system (physical catheters and electrodes inserted into the body) with a computational field theory approach. The mechanical insertion process is substituted by solving electromagnetic field equations (Laplace equation) with boundary conditions derived from surface measurements and anatomical models
2Device complexity
If a homogeneous chest wall model is used for computational reconstruction, then device complexity is reduced, but manufacturing precision of the reconstruction algorithm deteriorates
Solution Approach 1:
The patent applies local quality by assigning different electroconductivity values to different tissue regions within the chest wall model. Instead of using a single homogeneous parameter, the model incorporates spatially varying properties (muscle tissue, fat tissue, bone, lung) that reflect the actual local electrical characteristics of anatomical structures, thereby improving reconstruction accuracy
Solution Approach 2:
The patent performs preliminary action by pre-computing and storing the three-dimensional anatomical model of the chest wall and heart, including tissue segmentation and electroconductivity assignment, before the actual ECG data reconstruction process. This preparatory modeling work enables more accurate real-time or post-processing reconstruction
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables more precise noninvasive reconstruction of the heart's electric field and improved diagnosis of electrophysiological processes by accounting for tissue-specific electroconductivity, enhancing the accuracy of isopotential and isochronous maps and myocardium excitation dynamics.
Implementation Method 1
solving the Cauchy problem for the Laplace equation
Implementation Method 2
reconstructing the dynamics of the heart electric field
Implementation Method 3
fast multipole method for improved accuracy
Implementation Method 4
with an iterative algorithm and fast multipole method for improved accuracy
Data Source
AI summary
Reconstructing electrograms, whose experimental registration requires an invasive access, by computational way on unipolar ECGs recorded at 80 and more points of the chest surface. On the set of surface electrocardiograms for each discrete moment of the cardiocycle, values of the heart electric field potential at points of ECG-recording are determined, and a value of the electric field potential at each point of the chest surface is calculated by interpolation. Based on data of any visualization methodology, boundaries of chest and lungs surfaces and of the heart epicardial surface are determined. Further, a continuation of the electric field potential over the whole chest surface up to the heart epicardial surface with taking into account differences in electroconductivity of large anatomical structures of the chest is performed by computational way based on solution of the Cauchy problem for the Laplace equation in a piecewise-homogenous medium.