Dual-electrogram CRT Control for Ventricular Synchronization
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Solution Overview
Problem
Current cardiac resynchronization therapy (CRT) systems often rely on infrequent adjustments of CRT parameters, which can lead to suboptimal delivery of therapy due to changing patient conditions such as disease progression, physical activity, and myocardial remodeling, resulting in reduced ventricular synchronization and clinical benefits.
Innovation Solution
A medical device system that continuously monitors and adjusts CRT parameters, such as A-V and V-V delays, by analyzing cardiac electrograms from multiple electrode vectors to determine optimal synchronization, enabling real-time adaptation to patient-specific conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If CRT parameters are adjusted infrequently, then device complexity is reduced, but ventricular synchronization deteriorates due to changing patient conditions
Solution Approach 1:
The system continuously monitors ventricular activation timing from electrograms and uses this feedback to automatically adjust CRT parameters. The processing circuitry compares measured activation intervals against target values and modifies pacing delays accordingly, creating a closed-loop control system that adapts to changing patient conditions without requiring frequent manual interventions.
Solution Approach 2:
The device performs self-adjustment of CRT parameters by autonomously analyzing its own sensed electrogram data and modifying its pacing strategy. The implantable medical device independently determines optimal A-V and V-V delays based on real-time ventricular activation patterns, eliminating the need for external clinician intervention and frequent parameter reprogramming.
2Reliability
If CRT parameters are adjusted frequently based on real-time monitoring, then ventricular synchronization is improved, but device complexity and processing requirements increase
Solution Approach 1:
The system focuses on adjusting specific CRT parameters (A-V delay and V-V delay) based on changes in ventricular activation timing. By monitoring activation intervals and calculating their relationship to pacing delays, the device makes targeted parameter modifications rather than comprehensive reconfiguration, reducing overall system complexity while maintaining effective adaptation.
Solution Approach 2:
The system implements dynamic adjustment of CRT parameters by continuously adapting pacing delays based on real-time electrogram analysis. The processing circuitry modifies A-V and V-V delays in response to changing ventricular activation patterns, enabling the device to respond dynamically to patient condition changes such as disease progression, physical activity, and myocardial remodeling.
3Measurement precision
If multiple electrode vectors are used to monitor activation intervals, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system segments the electrogram signal into distinct components corresponding to different ventricular activation events. By identifying specific fiducial points (such as onset of QRS complex, peak of QRS, or other characteristic features) within the electrogram waveform, the device precisely measures activation intervals without requiring complex multi-vector electrode configurations.
Data Source
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Figure 3A~3B
AI summary
In some examples, controlling delivery of CRT includes controlling an implantable medical device to deliver ventricular pacing according to a sequence of different values of a CRT parameter, and acquiring first and second electrograms from respective first and second electrode vectors. For each value of the CRT parameter, a value of a metric of comparison of a first activation interval between occurrences of a first fiducial of a cardiac cycle and a second fiducial of the cardiac cycle detected in the first electrogram to a second activation interval between occurrences of the first fiducial and the second fiducial detected in the second electrogram may be determined. A target value of the metric of comparison may be identified and an updated value of the CRT parameter determined based on the target value. The system then may control the IMD to deliver ventricular pacing at the updated value of the CRT parameter.