ECG Waveform Timing Detector with Adaptive Threshold

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Solution Overview

Problem

Existing medical image diagnosis apparatuses, such as ultrasound and X-ray CT systems, face challenges in accurately detecting R waves from electrocardiographic waveforms due to erroneous detection of P waves and inability to reliably emphasize R waves, leading to inconsistent heart rate measurement.

Innovation Solution

An electrocardiographic (ECG) waveform timing detector is implemented, comprising an ECG waveform receiving circuit, a threshold value determining circuit, and a comparator. The threshold value determining circuit calculates heart rate and sets a threshold value for R wave detection, using past ECG waveforms to adjust and refine the detection trigger, ensuring accurate R wave identification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If R wave detection is performed using a fixed threshold or simple filtering, then the detection process is simple and fast, but the accuracy is insufficient due to erroneous detection of P waves and inability to reliably emphasize R waves

Engineering Contradiction:

ImproveR wave detection accuracyVSAvoiddetection process complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by calculating the heart rate from the ECG waveform before setting the detection threshold. The threshold is determined based on the calculated heart rate and waveform characteristics, which prepares the detection system in advance with optimized parameters specific to each patient's cardiac rhythm, thereby improving detection accuracy without requiring overly complex real-time processing

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The detection threshold is made dynamic rather than fixed. The threshold value changes adaptively based on the calculated heart rate and the specific characteristics of the ECG waveform. This dynamic adjustment allows the system to maintain high detection accuracy across varying heart rates and waveform morphologies while keeping the overall system relatively simple

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If filters are used to reduce the amplitude of non-R waves, then R waves are emphasized, but the process cannot ensure accurate detection and may still result in erroneous detections

Engineering Contradiction:

ImproveR wave detection accuracyVSAvoiddetection reliability

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The system changes the detection parameter (threshold value) based on the calculated heart rate and waveform characteristics. Instead of using a fixed threshold or simple amplitude reduction, the threshold is dynamically adjusted to match the specific ECG waveform being analyzed, ensuring that R waves are reliably distinguished from other waves without erroneous detections

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system employs feedback by using the calculated heart rate information to adjust the detection threshold. The heart rate calculation provides feedback about the waveform characteristics, which is then used to optimize the threshold setting, creating a closed-loop detection system that improves both accuracy and reliability

Inventive Principle:

Principle #23Feedback

3Reliability

If P waves are masked to prevent erroneous detection, then false positives are reduced, but true R waves may also be missed and heart rate measurement accuracy deteriorates

Engineering Contradiction:

Improvedetection consistencyVSAvoidheart rate measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary heart rate calculation and waveform analysis before setting the detection threshold. This preliminary action ensures that the threshold is optimized to distinguish R waves from P waves based on the actual waveform characteristics, preventing both false positives and false negatives without needing to mask any waves

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The detection threshold parameter is changed adaptively based on the calculated heart rate and waveform morphology. This parameter adjustment allows the system to maintain high detection consistency across different heart rates and waveform types while accurately identifying all true R waves without missing any beats

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11160486B2ECG waveform timing detector and medical image diagnosis apparatus

Publication Date: 2021.11.02 CANON MEDICAL SYST CORP

AI summary

According to one embodiment, an electrocardiographic (ECG) waveform timing detector includes an ECG waveform receiving circuit, a threshold value determining circuit, and a comparator. The threshold value determining circuit includes a heart rate calculating circuit, a threshold value setting circuit, and a comparing/determining circuit. The heart rate calculating circuit calculates the heart rate based on ECG waveform received by the ECG waveform receiving circuit. The threshold value setting circuit sets a threshold value. The comparing/determining circuit compares the heart rate with the number of R wave detection triggers detected using the threshold value to determine a threshold value for R wave detection trigger. The comparator compares the ECG waveform output from the ECG waveform receiving circuit with the threshold value for R wave detection trigger to output an R wave detection trigger.