Noise-Aware QT Interval Detection from Cardiac Signals

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Solution Overview

Problem

Existing cardiac signal analysis technologies face challenges in accurately detecting QT intervals due to noise and variability, which can lead to misinterpretation and increased risk of sudden cardiac death.

Innovation Solution

A method and device for identifying QT intervals by determining R-waves and T-waves in cardiac signals, filtering out noise, and using specific algorithms to calculate QT intervals, including an insertable cardiac monitor (ICM) with electrodes and processing circuitry to enhance accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If noise filtering is applied to cardiac signals, then measurement precision of QT interval is improved, but device complexity increases

Engineering Contradiction:
ImproveQT interval detection accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary noise filtering and signal conditioning before QT interval detection. The device pre-processes cardiac signals by filtering out electromagnetic interference and other noise components, establishing a cleaner signal baseline before performing the actual QT measurement, which improves accuracy without requiring complex post-processing

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces intermediate processing stages including signal amplification, filtering, and feature detection algorithms that act as mediators between the raw cardiac signal and the final QT interval measurement. These intermediary processes selectively enhance relevant signal components while suppressing noise, resolving the contradiction between measurement precision and device complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple beats are analyzed for QT interval, then reliability of QTc calculation is improved, but loss of time increases

Engineering Contradiction:
ImproveQTc interval reliabilityVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary identification and validation of qualified beats before QT interval measurement. The device pre-screens beats to ensure they meet quality criteria (appropriate morphology, absence of noise, correct R-wave detection), organizing valid beats for subsequent batch processing, which improves reliability while managing processing time efficiently

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adjusts the number of beats analyzed based on signal quality and clinical context. The device can adaptively select between analyzing a minimum number of beats for rapid assessment or a larger number for enhanced reliability, allowing flexible optimization between reliability and processing time requirements

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4125595B1Cardiac signal QT interval detection
Publication Date: 2025.10.15 MEDTRONIC INC
  • EP4125595B1 patent drawingFigure 1
  • EP4125595B1 patent drawingFigure 2
  • EP4125595B1 patent drawingFigure 3

AI summary

An example device for detecting one or more parameters of a cardiac signal is disclosed herein. The device includes one or more electrodes and sensing circuitry configured to sense a cardiac signal via the one or more electrodes. The device further includes processing circuitry configured to determine an R-wave of the cardiac signal and determine whether the R-wave is noisy. Based on the R-wave being noisy, the processing circuitry is configured to determine whether the cardiac signal around a determined T-wave is noisy. Based on the cardiac signal around the determined T-wave not being noisy, the processing circuitry is configured to determine a QT interval or a corrected QT interval based on the determined T-wave and the determined R-wave.