Defibrillation Device R-Wave Detection Using Differential Thresholds
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Solution Overview
Problem
Conventional defibrillation catheter systems face challenges in accurately detecting the R-wave in electrocardiogram waveforms, leading to potential erroneous voltage applications and ventricular fibrillation, as they often fail to distinguish between R-waves and T-waves during non-absolute refractory periods.
Innovation Solution
An electric device for defibrillation that generates an enable signal only after a peak in the R-wave is surpassed, using specific differential value thresholds (C1, C2, and C3) to differentiate between R-waves and T-waves, ensuring accurate detection and avoiding erroneous voltage applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional R-wave detection methods are used, then defibrillation can be performed during the absolute refractory period, but T-waves may be erroneously recognized as R-waves causing ventricular fibrillation
Solution Approach 1:
The patent applies parameter changes by using multiple differential value thresholds (C1, C2, C3) to characterize different phases of the R-wave. The method detects the rise phase (differential value ≥ C1), peak phase (differential value between C2 and C1), and fall phase (differential value ≤ C3) of the R-wave, ensuring accurate identification by verifying the sequence of these parameter changes rather than relying on a single threshold.
Solution Approach 2:
The patent implements feedback by continuously monitoring the differential values of the ECG waveform and comparing them against the predefined thresholds C1, C2, and C3. The system adjusts its detection state based on the current differential value, transitioning between detection states (rising edge detected, peak detected, falling edge detected) according to the feedback from the differential value comparisons, thereby accurately tracking the R-wave morphology.
2Device complexity
If a single threshold is used for R-wave detection, then the detection mechanism is simple, but the accuracy of distinguishing R-waves from T-waves is insufficient
Solution Approach 1:
The patent uses parameter changes by defining three distinct threshold levels (C1, C2, C3) that correspond to different phases of the R-wave. Instead of a single threshold, the system monitors how the differential value changes across these multiple parameters, detecting the characteristic pattern of increase (≥C1), peak (between C2 and C1), and decrease (≤C3) that defines a true R-wave.
Solution Approach 2:
The patent applies segmentation by dividing the R-wave detection process into three distinct phases based on differential value ranges: the rising phase (differential value ≥ C1), the peak phase (differential value between C2 and C1), and the falling phase (differential value ≤ C3). This segmentation allows the system to verify the complete morphology of the R-wave rather than relying on a single point measurement.
Data Source
AI summary
An object of the present invention is to provide a new electric device for defibrillation and a method for generating a defibrillation signal. The electric device for defibrillation includes an electrocardiogram waveform input unit; and an enable signal generating unit, wherein the electric device for defibrillation is configured to generate an enable signal from the enable signal generating unit after a peak of an event is surpassed and when or after condition 1 is satisfied, the event being estimated to be an R-wave of an electrocardiogram waveform, the electrocardiogram waveform being obtained from a human body and inputted from the electrocardiogram waveform input unit, and the condition 1 is that a differential value in a differentiated waveform generated based on the electrocardiogram waveform, which corresponds to the event estimated to be the R-wave, is a negative constant C3 value or less.