Intracardiac Electrogram Frequency Analysis for Lesion Durability
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Solution Overview
Problem
Current cardiac ablation techniques lack effective methods to evaluate the efficacy and durability of lesions formed, particularly in determining whether they will sufficiently disrupt abnormal electrical signals and persist chronically.
Innovation Solution
The disclosure presents techniques to analyze intracardiac electrogram (iEGM) signals in both time and frequency domains to assess lesion formation, using specific frequency bands and other biological measurements to develop a lesion durability index, which helps predict chronic lesion size and persistence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ablation energy is delivered to form a cardiac lesion, then unwanted electrical signal conduction is blocked, but the efficacy and durability of the lesion cannot be effectively evaluated
Solution Approach 1:
The system continuously monitors intracardiac electrogram signals during and after ablation, providing real-time feedback on lesion formation and evolution. By analyzing frequency band changes in the electrogram signals, the system delivers feedback information to the practitioner about lesion efficacy and durability, enabling informed decisions during the procedure.
Solution Approach 2:
The patent replaces direct mechanical or visual assessment of lesion durability with electrical signal analysis. Instead of relying on anatomical visualization or post-procedure histology, the system uses frequency-domain analysis of electrogram signals to non-invasively assess lesion characteristics and predict chronic persistence.
2Measurement precision
If multiple frequency bands are analyzed to assess lesion formation, then comprehensive lesion evaluation is achieved, but signal processing complexity increases
Solution Approach 1:
The patent segments the electrogram signal into multiple frequency bands (e.g., low frequency 0-8 Hz, mid frequency 8-30 Hz, high frequency 30-500 Hz) and analyzes each band separately for specific lesion characteristics. This segmentation allows comprehensive evaluation while maintaining manageable processing complexity through targeted analysis of each frequency range.
Solution Approach 2:
Different frequency bands are assigned different analytical weights and thresholds based on their specific diagnostic value. The system applies local quality principles by treating each frequency band differently - for example, placing higher emphasis on low frequency changes for chronic lesion assessment while using high frequency changes for acute lesion evaluation - thereby optimizing measurement precision without uniform complexity across all analysis components.
3Measurement precision
If iEGM amplitude reduction is observed in high frequency range immediately after ablation, then acute lesion formation is indicated, but chronic lesion persistence cannot be determined
Solution Approach 1:
The system performs preliminary analysis of iEGM frequency band changes immediately after ablation to assess acute lesion formation. By establishing baseline acute changes and tracking their evolution over time, the system prepares the groundwork for determining chronic persistence without requiring separate acute/chronic analysis protocols.
Solution Approach 2:
The patent employs dynamic analysis by continuously monitoring frequency band characteristics at multiple time points (immediate post-ablation, 5 minutes, 30 minutes, and later). The system analyzes how frequency content evolves from acute to chronic phases, using dynamic thresholds and time-dependent criteria to distinguish transient changes from persistent lesion effects.
Data Source
AI summary
Evaluating a cardiac lesion formed by an ablation procedure, by receiving, by processing circuitry and following conclusion of delivery of ablation energy, a bioelectrical signal from an electrode proximate to a target location of cardiac tissue for the cardiac lesion; determining, by the processing circuitry, one or more characteristics of the received bioelectrical signal in a frequency band of the received bioelectrical signal; and estimating, by the processing circuitry, an efficacy of the cardiac lesion based on a comparison of the determined amplitude of the bioelectrical signal and a threshold amplitude.