Atrial Fibrillation Detection Using Ventricular Electrograms

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Solution Overview

Problem

Current ambulatory medical devices, including implantable, wearable, and handheld devices, often lack dedicated atrial sensing capability, which can lead to inadequate detection of atrial fibrillation (AF) in patients, particularly those with heart failure, where AF is common, making it difficult for clinicians to provide effective diagnostic and therapeutic interventions.

Innovation Solution

The implementation of an ambulatory medical device system that includes a method for detecting atrial fibrillation by sensing cardiac signals, using multiple detection criteria such as V-V interval dispersion, double decrement, Wenkebach regularity, and noise analysis, allowing for the accurate identification and classification of AF episodes, even without dedicated atrial sensing electrodes, and incorporating a 'look-back' feature to account for missed episodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If ambulatory medical devices do not include dedicated atrial sensing capability, then device complexity is reduced, but atrial fibrillation detection accuracy deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidAF detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies multi-functionality by enabling ventricular sensing electrodes to perform dual functions: traditional ventricular activity sensing and indirect atrial fibrillation detection. The device uses existing ventricular electrograms to detect AF episodes through algorithms that identify characteristic ventricular responses to atrial fibrillation, eliminating the need for dedicated atrial sensing electrodes while maintaining detection capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses ventricular electrograms as an intermediary to indirectly detect atrial fibrillation. Instead of directly sensing atrial activity, the system analyzes ventricular electrical signals that are influenced by atrial fibrillation, using the ventricular response as a mediator to infer the presence and characteristics of AF episodes

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple detection criteria are used to improve AF detection accuracy, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
ImproveAF detection accuracyVSAvoiddetection algorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the AF detection process into multiple independent criteria that can be evaluated separately: V-V interval dispersion analysis, double decrement detection, Wenkebach regularity assessment, and noise analysis. Each criterion operates as an independent detection module that contributes to the overall AF identification, allowing the system to achieve high accuracy through the combination of specialized sub-algorithms

Inventive Principle:
Principle #1Segmentation

3Reliability

If the device implements look-back feature to detect missed AF episodes, then AF detection completeness is improved, but processing time increases

Engineering Contradiction:
ImproveAF detection completenessVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary action by continuously analyzing ventricular electrograms in real-time and maintaining a look-back window that proactively identifies potential AF episodes before they are fully completed. The system continuously evaluates detection criteria on incoming data streams and can trigger AF detection algorithms on stored historical data when suspicious patterns are detected, ensuring complete capture of AF episodes while minimizing retrospective processing requirements

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3592419B1Post-hoc atrial fibrillation detection
Publication Date: 2021.07.14 CARDIAC PACEMAKERS INC
  • EP3592419B1 patent drawingFigure 1
  • EP3592419B1 patent drawingFigure 2
  • EP3592419B1 patent drawingFigure 3

AI summary

An apparatus comprises an arrhythmia detection circuit configured to: detect atrial arrhythmia in a first portion of a sensed cardiac signal using a first arrhythmia detection criteria, wherein the sensed cardiac signal is representative of cardiac activity of a subject; and upon detection of the atrial arrhythmia, analyze a second portion of the cardiac signal that is prior in time to the first portion using a second different arrhythmia detection criteria to detect the presence or absence of the atrial arrhythmia in the second portion of the cardiac signal.