Endocardial Acceleration Signal Analysis for CRT Monitoring
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Solution Overview
Problem
Current methods for evaluating the effectiveness of Cardiac Resynchronization Therapy (CRT) are cumbersome and costly, requiring frequent ultrasound evaluations or invasive bioimpedance measurements, which are not practical for frequent monitoring and may not accurately reflect the mechanical and hemodynamic performance of the heart.
Innovation Solution
An analysis device that processes endocardial acceleration signals to extract relevant information about the heart's mechanical and hemodynamic activity, accounting for cycle-to-cycle variations and specific components of the signal, such as EA1 and EA2, to provide a more specific and relevant assessment of cardiac performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasound evaluation is used to estimate characteristic systole times, then measurement precision is improved, but loss of time and productivity deteriorate due to lengthy procedures requiring hospital environment and qualified personnel
Solution Approach 1:
The patent replaces the mechanical/physical ultrasound evaluation system with an electronic signal processing system that analyzes endocardial acceleration signals. The accelerometer-based measurement system substitutes the ultrasound device, enabling automated extraction of systole time characteristics through digital signal processing rather than manual ultrasound interpretation.
Solution Approach 2:
The implanted device performs self-monitoring and self-evaluation of cardiac function by continuously acquiring and processing endocardial acceleration signals. The system automatically determines characteristic systole times without requiring external hospital equipment or qualified personnel intervention, enabling patients to monitor their own cardiac performance at home.
2Measurement precision
If ultrasound evaluation is used to estimate characteristic systole times, then measurement precision is improved, but device complexity and ease of operation worsen due to requirement of hospital environment and qualified personnel
Solution Approach 1:
The implanted device performs self-monitoring and self-evaluation of cardiac function by continuously acquiring and processing endocardial acceleration signals. The system automatically determines characteristic systole times without requiring external hospital equipment or qualified personnel intervention, enabling patients to monitor their own cardiac performance at home.
Solution Approach 2:
The patent introduces an intermediary integrated circuit within the implanted device that automatically processes raw endocardial acceleration signals and extracts characteristic systole times. This intermediary processing layer eliminates the need for complex external ultrasound equipment and expert interpretation, translating raw sensor data into clinically relevant metrics automatically.
3Ease of operation
If intracardiac bioimpedance measurement is used to evaluate ventricle synchronization, then ease of operation is improved, but measurement precision deteriorates as it only provides indirect information about cardiac output
Solution Approach 1:
The patent replaces electrical bioimpedance measurement with direct mechanical acceleration measurement. The accelerometer directly senses mechanical vibrations of the heart wall, providing explicit information about myocardial contraction dynamics rather than indirect electrical proxies. This substitution of measurement modality (mechanical vs. electrical) delivers superior precision in assessing mechanical performance.
Solution Approach 2:
The patent segments the continuous endocardial acceleration signal into distinct cardiac cycle phases by identifying characteristic waveform features. By dividing the signal into systolic and diastolic components, the system can precisely measure characteristic systole times and evaluate ventricular synchronization with high temporal resolution, overcoming the indirect nature of bioimpedance measurements.
4Productivity
If endocardial acceleration signal analysis is performed without accounting for cycle-to-cycle variations, then productivity is improved through simpler processing, but measurement precision deteriorates due to falsified analysis results
Solution Approach 1:
The patent applies periodic action by analyzing multiple consecutive cardiac cycles and computing average characteristic systole times. By repeating the measurement across several cycles and averaging the results, the system eliminates random cycle-to-cycle variations while preserving the true underlying cardiac performance metrics, thereby maintaining both precision and processing efficiency.
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 allows for continuous monitoring and optimization of CRT, improving the specificity and relevance of results, enabling better hemodynamic performance estimation and optimal ventricular resynchronization therapy adjustment, even during exercise.
Implementation Method 1
endocardial acceleration, which is measured by an accelerometer directly in contact with the heart muscle
Data Source
Figure 1~3
Figure 2
Figure 4~5(b)
AI summary
This device includes preprocessing means comprising: means (100) for slicing the collected EA signal into EA sub-signals, each over the duration of a cardiac cycle; separating means (110) for isolating, in each of the EA sub-signals, EA1 and EA2 components associated with the two major cardiac sounds; correlating means (120, 120'), operating separately on each of the EA1 and EA2 components, for recalibrating each of the sub-signals with respect to a maximum correlation, so as to deliver a recalibrated EA1 component and an EA2 component; and associating means (130) for determining, from the EA1 and EA2 components delivered by the correlating means, an average EA1 component and an average EA2 component, and for combining these average EA1 and EA2 components so as to produce an overall average EA signal over one cycle.The device extracts from this information temporal markers of characteristic moments of the cardiac cycle, including markers of the opening and closing times of the aortic valve.