Effective Capture Test for Cardiac Resynchronization Therapy
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Solution Overview
Problem
Cardiac pacing systems often fail to achieve effective capture of ventricles due to suboptimal lead placement, sensed or paced atrioventricular delays, and potential migration or dislodgement of pacing leads, necessitating a method to automatically determine and ensure optimal ventricular capture.
Innovation Solution
The implementation of an effective capture test that evaluates signal characteristics such as maximum and minimum amplitudes and times, along with baseline values, to determine if a ventricular pacing stimulus effectively captures the ventricle, and adjusts settings to improve capture efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional capture management algorithms are used, then the system is simple to operate, but the reliability of ventricular capture is insufficient due to suboptimal lead placement and timing
Solution Approach 1:
The system performs preliminary actions by delivering test pacing stimuli at different timings (S1, S2, S3) and energies before normal operation to determine optimal capture conditions. The effective capture test proactively identifies optimal atrioventricular delays and pacing parameters in advance, ensuring reliable capture during subsequent therapy delivery without requiring complex real-time adjustments.
Solution Approach 2:
The system implements feedback by sensing ventricular electrograms and analyzing signal characteristics (amplitude, morphology, timing) to determine whether effective capture occurred. The processor uses this feedback to automatically identify optimal pacing parameters and adjust timing intervals, creating a closed-loop system that continuously verifies and optimizes capture reliability.
2Productivity
If manual assessment of ventricular capture is performed, then the measurement process is simple, but the time consumption and productivity are reduced
Solution Approach 1:
The system performs self-service by automatically delivering test stimuli, sensing electrogram signals, analyzing capture effectiveness, and determining optimal pacing parameters without requiring continuous manual intervention. The processor autonomously evaluates signal characteristics and adjusts timing intervals, enabling the device to self-optimize capture conditions and significantly improving assessment efficiency.
Solution Approach 2:
The system replaces manual mechanical assessment with automated electronic evaluation. Instead of manual observation and adjustment, the processor electronically analyzes electrogram signal characteristics (amplitude, morphology, timing) and automatically determines optimal capture parameters, substituting human operator actions with automated computational processes that increase productivity.
3Reliability
If pacing leads are placed in non-optimal locations or migrate, then the device structure remains simple, but the reliability of capture is compromised
Solution Approach 1:
The system implements dynamics by continuously testing and adjusting pacing parameters rather than relying on fixed lead placement. The effective capture test dynamically identifies optimal atrioventricular delays and pacing timing intervals, allowing the system to adapt to lead migration or suboptimal placement by finding alternative optimal parameters that ensure reliable capture regardless of lead position.
Solution Approach 2:
The system uses parameter changes by varying pacing timing intervals (S1-S2-S3 sequences) and energy levels to determine optimal capture conditions. By systematically changing these parameters and evaluating capture effectiveness at each setting, the system can compensate for lead placement issues and identify parameter combinations that achieve reliable capture even with non-ideal lead positions.
4Measurement precision
If multiple test pacing stimuli are delivered to determine optimal capture, then the reliability of capture determination improves, but the use of energy and time increase
Solution Approach 1:
The system applies partial action by delivering a limited sequence of test stimuli (S1, S2, S3) rather than exhaustive testing. The protocol uses a structured approach where S1 establishes baseline capture, S2 tests for optimal timing, and S3 confirms effectiveness, providing sufficient precision for clinical decision-making without excessive energy consumption. The test delivers just enough stimuli to determine capture status with acceptable accuracy.
Solution Approach 2:
The system uses periodic action by delivering test pacing stimuli at structured intervals and using refractory periods to minimize energy consumption. The S1-S2-S3 sequence is delivered periodically during device operation, utilizing natural cardiac cycles and refractory periods to schedule tests when energy demand is lower, thereby achieving precise measurement while managing energy usage efficiently.
Data Source
AI summary
The present disclosure pertains to cardiac pacing methods and systems, and, more particularly, to cardiac resynchronization therapy (CRT). In particular, the present disclosure pertains to determining the efficacy of CRT through use of an effective capture test (ECT). One or more embodiments comprises sensing a signal in response to a ventricular pacing stimulus. Through signal processing, a number of features are parsed from the signal. Exemplary features parsed from the signal include a maximum amplitude, a maximum time associated with the maximum amplitude, a minimum amplitude, and a minimum time associated with the minimum amplitude. The data is evaluated through use of the ECT. By employing the ECT, efficacy of CRT is easily and automatically evaluated.