CRT System Pseudo-Fusion Detection via Multi-Electrode Morphology
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Solution Overview
Problem
Current cardiac resynchronization therapy (CRT) systems face challenges in distinguishing between effective left ventricular (LV) pacing and pseudo-fusion, leading to inefficient pacing and potential battery depletion, as existing algorithms are limited in identifying pseudo-fusion without a positive LV electrogram deflection.
Innovation Solution
The system utilizes multiple LV electrodes to spatiotemporally characterize propagating wave fronts, analyzing conduction patterns and electrogram morphologies across multiple electrodes to differentiate between effective LV pacing and pseudo-fusion, adjusting CRT parameters accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a device-based algorithm analyzes EGM signals with limited criteria (positive deflection detection), then pseudo-fusion can be identified in some cases, but it fails to identify pseudo-fusion without positive LV EGM deflection
Solution Approach 1:
The patent transitions from analyzing a single EGM signal dimension to analyzing multiple signal dimensions simultaneously. It compares morphology across multiple sensing vectors (RV-LV, LVM2-RV, LVD1-RV) and evaluates multiple temporal characteristics (pre-pacing negative deflection, post-pacing positive deflection, morphology similarity). This multi-dimensional analysis enables detection of pseudo-fusion cases that lack positive LV EGM deflection while maintaining algorithmic feasibility through structured comparison criteria.
2Reliability
If additional ventricular paced events are delivered to ensure effective pacing, then effective LV capture is maintained, but battery depletion occurs
Solution Approach 1:
The patent implements a feedback mechanism where the detected pseudo-fusion information is used to adjust pacing delivery. When pseudo-fusion is detected through multi-vector morphology comparison, the system modifies pacing parameters (such as extending the LV pacing window or adjusting pacing amplitude) to ensure effective capture. This feedback loop prevents unnecessary pacing events while maintaining reliable LV capture, thereby conserving battery energy.
3Reliability
If pacing delays (RVLV and LVLV) are set longer to allow wave front propagation, then complete ventricular depolarization is achieved, but pseudo-fusion occurs with intrinsic depolarization wave fronts
Solution Approach 1:
The patent applies preliminary action by detecting pseudo-fusion conditions before they compromise pacing effectiveness. Through pre-pacing negative deflection detection and morphology comparison across multiple vectors, the system identifies when intrinsic wave fronts are approaching the pacing site. This allows the device to adjust pacing timing or amplitude in advance, ensuring complete ventricular depolarization while preventing pseudo-fusion from undermining pacing effectiveness.
Data Source
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AI summary
A system is provided for, under control of one or more processors (164, 602), delivering cardiac resynchronization therapy (CRT) at one or more pacing sites. The processors (164, 602) obtain cardiac signals, associated with a candidate beat, from multi-site left ventricular (MSLV) electrodes (132-138) distributed along a left ventricle and analyze the cardiac signals to collect at least one of a MSLV conduction pattern or a MSLV morphology. The processors (164, 602) compare at least one of the MSLV conduction pattern or MSLV morphology to one or more associated templates (402, 404, 422, 424, 442, 444, 464, 464). The processors (164, 602) then label the candidate beat as a pseudo-fusion beat based on the comparing and adjust the CRT based on the labeling.