R-Wave Detection Using Fixed Threshold and Adaptive Signal Gain
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional implantable cardiac devices face challenges in accurately detecting R-waves without mistaking other morphological features of the ECG/IEGM signal, often requiring dynamic adjustment of detection thresholds which can be complex and prone to errors.
Innovation Solution
Implementing a method that uses a fixed detection threshold with adjustable gain to detect R-waves, where the gain is adjusted based on peak amplitudes of the digital signal, allowing for dynamic sensitivity control without altering the detection threshold, using an N-bit analog-to-digital converter and a multiplier to process the signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dynamic adjustment of detection threshold is used to detect R-waves, then detection sensitivity is improved, but device complexity increases and errors are more likely to occur
Solution Approach 1:
The patent changes the parameter being adjusted from detection threshold to signal gain. By adjusting the gain of the sensed signal rather than the threshold, the system achieves dynamic sensitivity control while maintaining a fixed threshold comparator, thereby reducing circuit complexity while preserving detection accuracy
Solution Approach 2:
The patent introduces a gain adjustment stage as an intermediary between the signal source and the fixed threshold comparator. This intermediary allows the signal amplitude to be dynamically scaled before comparison, enabling adaptive sensitivity without requiring a dynamic threshold mechanism
2Measurement precision
If dynamic adjustment of detection threshold is used to detect R-waves, then detection sensitivity is improved, but reliability decreases due to more errors
Solution Approach 1:
The patent changes the parameter being adjusted from detection threshold to signal gain. By adjusting the gain of the sensed signal rather than the threshold, the system achieves dynamic sensitivity control while maintaining a fixed threshold comparator, thereby reducing circuit complexity while preserving detection accuracy
Solution Approach 2:
The system uses feedback from detected R-wave characteristics to dynamically adjust the gain parameter. This feedback mechanism allows the system to adapt to varying signal conditions while maintaining reliable detection through a stable fixed threshold
3Device complexity
If fixed detection threshold is used, then device complexity is reduced, but detection sensitivity becomes insufficient for varying signal conditions
Solution Approach 1:
The patent changes the parameter being adjusted from detection threshold to signal gain. By adjusting the gain of the sensed signal rather than the threshold, the system achieves dynamic sensitivity control while maintaining a fixed threshold comparator, thereby reducing circuit complexity while preserving detection accuracy
Solution Approach 2:
The patent applies dynamics by making the gain parameter adjustable and adaptive based on signal characteristics, while keeping the threshold static. This dynamic gain control allows the system to maintain optimal detection sensitivity across varying signal conditions without requiring dynamic threshold adjustment
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Devices and methods for dynamically controlling sensitivity associated with detecting R-waves while maintaining the fixed detection threshold are described herein. One such method includes sensing an analog signal indicative of cardiac electrical activity, converting the analog signal indicative of cardiac electrical activity to a digital signal indicative of cardiac electrical activity, and detecting R-waves by comparing the digital signal indicative of cardiac electrical activity to a fixed detection threshold to thereby detect threshold crossings that corresponds to R-waves. The method further includes selectively adjusting a gain applied to the digital signal indicative of cardiac electrical activity to thereby selectively adjust a sensitivity associated with the detecting R-waves, while maintaining the fixed detection threshold.