LV Pacing Electrogram Amplitude for Scar Substrate Identification
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Solution Overview
Problem
Current cardiac pacing technologies face challenges in effectively identifying and avoiding abnormal cardiac substrates, such as scar tissue, during left-ventricular pacing, which can reduce the efficacy of cardiac resynchronization therapy (CRT) by failing to accurately distinguish between normal and abnormal tissue using existing mapping procedures.
Innovation Solution
A system comprising an implantable left-ventricular lead with a bipolar electrode pair that senses cardiac electrogram signals and delivers pacing pulses to determine the amplitude of depolarizations, allowing for the identification of abnormal cardiac substrate based on specific amplitude thresholds during LV pacing, enabling the avoidance of abnormal tissue during lead implantation and therapy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional LV mapping procedures are used to identify scar substrate, then abnormal substrate can be detected, but the accuracy is insufficient to reliably distinguish between normal and abnormal tissue
Solution Approach 1:
The patent changes the measurement parameter from electrogram amplitude during intrinsic conduction to depolarization amplitude during LV pacing. This parameter change enables more reliable distinction between normal and abnormal tissue by measuring the heart's electrical response to controlled pacing stimuli, which provides clearer differentiation criteria than passive electrogram amplitude measurement.
Solution Approach 2:
The system performs preliminary LV pacing before final lead placement to assess tissue response. By delivering test pacing pulses and measuring depolarization amplitudes in advance, the system identifies suitable pacing sites that will effectively propagate depolarization, ensuring reliable CRT delivery before committing to permanent implantation.
2Productivity
If LV pacing is delivered via an electrode located proximate abnormal substrate, then pacing can be delivered, but the effectiveness of CRT is reduced due to failure to propagate depolarization
Solution Approach 1:
The system uses feedback from measured depolarization amplitudes to evaluate the quality of potential pacing sites. By measuring the amplitude of depolarizations during test pacing and comparing them against threshold criteria, the system provides feedback on whether a given site is suitable for effective CRT delivery, enabling selection of sites with reliable depolarization propagation.
Solution Approach 2:
The patent employs a dynamic assessment approach where multiple test pacing pulses are delivered at different locations and the depolarization responses are evaluated in real-time. This dynamic evaluation allows the system to identify sites that demonstrate adequate depolarization propagation capability before final lead placement, ensuring optimal CRT effectiveness.
3Measurement precision
If a bipolar electrode pair is used to sense electrogram signals during intrinsic conduction, then abnormal substrate can be identified, but the threshold for identifying scar is not valid during LV pacing
Solution Approach 1:
The system performs preliminary assessment during LV pacing before final implantation. By delivering test pacing pulses and measuring depolarization amplitudes in advance, the system establishes pacing-specific threshold criteria that are valid for evaluating tissue suitability during the actual therapeutic pacing mode, rather than relying on thresholds derived from intrinsic conduction.
Solution Approach 2:
The patent transitions the measurement parameter from passive electrogram amplitude during intrinsic conduction to active depolarization amplitude during LV pacing. This parameter change creates measurement conditions that are directly applicable to therapeutic pacing, making the identification criteria versatile and valid for the actual treatment mode.
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 precise identification of abnormal cardiac substrate during LV pacing, improving the placement of pacing leads and enhancing the effectiveness of CRT by distinguishing between normal and abnormal tissue with higher accuracy compared to traditional mapping methods.
Implementation Method 1
An LV lead implanted on the left ventricle includes a bipolar electrode pair to sense an LV bipolar cardiac electrogram signal of LV tissue proximate the bipolar electrode pair
Data Source
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AI summary
Techniques for identifying abnormal cardiac substrate, e.g., scar substrate, may be implemented, as an example, during implantation of a left-ventricular (LV) lead, e.g., for cardiac resynchronization therapy (CRT), which may enable placement of the LV lead to avoid the abnormal cardiac substrate. An example system for identifying abnormal cardiac substrate comprises at least one implantable LV lead comprising at least one bipolar electrode pair configured to sense a LV bipolar cardiac electrogram signal of LV tissue proximate the electrode pair. The system delivers cardiac pacing pulses to a left ventricle via at least one electrode of the LV lead, which may be different then the electrodes of the bipolar pair, and which may be spaced at least a threshold distance from the bipolar pair of electrodes. The amplitude of paced depolarizations in the bipolar electrogram indicates whether tissue proximate the bipolar electrode pair comprises abnormal cardiac substrate.