Non-invasive Cardiac Electrogram Mapping via MRI Segmentation
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Solution Overview
Problem
Current methods for creating cardiac electrogram characteristic maps for catheter ablation of ventricular tachycardia are invasive, time-consuming, and limited by sampling density, making them inefficient and prone to errors due to hemodynamic instability and poor catheter contact.
Innovation Solution
A non-invasive method using three-dimensional image data from cardiac magnetic resonance imaging (MRI) to segment scar and normal myocardium tissue, determining tissue thickness, and generating electrogram characteristic maps based on multivariate regression models to predict voltage and other electrogram characteristics, thereby creating accurate, pre-procedural maps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive electroanatomic mapping (EAM) is performed during sinus rhythm or ventricular pacing to create substrate maps, then EGM characteristic maps can be obtained for catheter ablation, but procedural time is significantly prolonged and sampling density is limited
Solution Approach 1:
The patent performs CMR imaging and creates scar maps before the catheter ablation procedure to pre-identify potential ablation targets. This preliminary substrate characterization allows the procedure to focus on specific regions of interest rather than requiring comprehensive invasive mapping during the procedure, significantly reducing procedural time while maintaining identification accuracy
Solution Approach 2:
The patent creates a virtual electroanatomic map by registering CMR-derived scar information to a 3D model of the left ventricle. This virtual map serves as a copy or surrogate of the actual substrate, allowing clinicians to plan ablation strategies without requiring extensive invasive mapping during the procedure
2Measurement precision
If invasive EAM is used to map substrate during sinus rhythm, then EGM characteristics can be measured, but the method is limited by sampling density and catheter contact quality
Solution Approach 1:
The patent replaces the mechanical catheter-based measurement system with a non-invasive CMR imaging system. Instead of physically contacting the myocardium with catheters to record EGMs, the system uses magnetic resonance imaging to directly visualize scar tissue and derive electrogram characteristics from tissue properties, eliminating catheter contact issues and improving sampling density
Solution Approach 2:
The patent changes the measurement parameters from electrical signals (EGMs) recorded by catheters to magnetic resonance signal intensities and tissue characteristics. By measuring scar transmurality, tissue heterogeneity, and other structural parameters via CMR, the system derives EGM characteristics indirectly through established relationships between tissue properties and electrical behavior
3Area of stationary object
If scar maps from LGE-CMR are imported into the procedure, then scar location and extent can be visualized, but transmurality and tissue heterogeneity are difficult to display
Solution Approach 1:
The patent extends the visualization from two-dimensional CMR image planes to a three-dimensional model of the left ventricle. By mapping scar information onto the 3D LV geometry, the system can display transmurality as the extent of scar through the wall thickness and represent tissue heterogeneity in three-dimensional space, providing comprehensive spatial information that cannot be conveyed in 2D images alone
4Measurement precision
If invasive mapping is performed during hemodynamically unstable VT, then VT circuit can be mapped, but the procedure is prone to errors due to instability and poor catheter contact
Solution Approach 1:
The patent performs substrate mapping during stable sinus rhythm before inducing or treating VT. This preliminary mapping identifies scar regions and potential VT circuits when hemodynamic conditions are stable, avoiding the errors and uncertainties associated with mapping during unstable tachycardia while still providing accurate guidance for subsequent VT ablation
Data Source
AI summary
A non-invasive method of producing a three-dimensional cardiac electrogram characteristic map for use in catheter ablation of ventricular tachycardia includes receiving left ventricle three-dimensional image data of a patient's heart; segmenting a left ventricle image of the patient's heart based on the left ventricle three-dimensional image data into scar tissue, normal myocardium tissue and left ventricle cavity regions; determining scar tissue thickness and normal myocardium tissue thickness for a plurality of portions of the left ventricle image of the patient's heart; receiving predetermined data that associate a value of at least one electrogram characteristic to each scar tissue thickness and each normal myocardium tissue thickness for the plurality of portions of said left ventricle image of said patient's heart; and generating the three-dimensional cardiac electrogram characteristic map of the at least one electrogram characteristic corresponding to the left ventricle image of the patient's heart based on the predetermined data.