Implantable Cardiac Device T-Wave Alternans Detection

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Solution Overview

Problem

Current methods for detecting T-wave alternans patterns require long-term surface ECG recordings and robust computational analysis, making them inconvenient for continuous monitoring, especially in patients with implanted cardiac devices.

Innovation Solution

An implantable cardiac device system and method that detects intrinsic or induced premature contractions of the ventricles, measuring T-wave metrics in a specified number of beats to determine the presence of T-wave alternans, allowing for continuous monitoring without the need for surface ECGs or extensive computational resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If surface ECG recordings with robust computational analysis are used to detect T-wave alternans, then measurement precision is improved, but device complexity and ease of operation deteriorate

Engineering Contradiction:

Improvedetection accuracy of T-wave alternansVSAvoidcomplexity of computational analysis system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential T-wave measurement from the complex surface ECG system, using intracardiac electrograms from existing implantable devices. This eliminates the need for complex surface ECG recording systems while maintaining detection capability through focused measurement of T-wave amplitude and timing from simplified intracardiac signals.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent enables the implantable cardiac device itself to perform T-wave alternans detection using its existing sensing and processing capabilities. The device uses its own intracardiac electrogram recordings and computational resources to detect TWA, eliminating the need for external surface ECG systems and making the system self-sufficient.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If long-term surface ECG recordings are performed to detect T-wave alternans, then measurement precision is improved, but loss of time and ease of operation worsen

Engineering Contradiction:

Improvedetection accuracy of T-wave alternansVSAvoidduration of monitoring required

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables continuous T-wave alternans monitoring through the implantable device that continuously records intracardiac electrograms. Unlike intermittent surface ECG recordings, the implantable device provides uninterrupted monitoring, allowing TWA detection to occur continuously without requiring scheduled recording sessions or prolonged external monitoring periods.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent uses premature ventricular contractions as natural triggers that occur beforehand to initiate T-wave measurement sequences. When a PVC occurs, the system automatically measures T-waves in subsequent beats, using the premature event as a preliminary signal to start the detection process, thereby reducing the need for continuous active monitoring.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If surface ECG methods are used for T-wave alternans detection, then measurement precision is improved, but adaptability to implantable devices deteriorates

Engineering Contradiction:

Improvedetection accuracy of T-wave alternansVSAvoidcompatibility with implantable cardiac devices

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent makes the implantable cardiac device perform multiple functions: its existing electrodes and sensing circuits simultaneously serve for routine cardiac monitoring and for T-wave alternans detection. The intracardiac electrogram recording system is used dually for both standard arrhythmia detection and specialized TWA measurement, eliminating the need for separate surface ECG equipment and improving adaptability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses the intracardiac electrogram as an intermediary signal that bridges the gap between implantable device capabilities and T-wave alternans detection requirements. The IEGM serves as a mediator that contains sufficient T-wave information for alternans detection while being naturally produced by the implantable device's existing sensing system.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7756571B1Methods and systems for detecting the presence of T-wave alternans

Publication Date: 2010.07.13 PACESETTER INC

AI summary

Embodiments of the present invention relate to implantable systems, and method for use therein, that can detect T-wave alternans. In accordance with specific embodiments of the present invention, intrinsic premature contractions of the ventricles are detected, and at least one metric of T-waves is measured in a specified number of beats that follow each detected intrinsic premature contraction of the ventricles. A determination of whether T-wave alternans are present is made based on the measured T-wave metrics. In alternative embodiments, rather than waiting for intrinsic premature contractions of the ventricles, premature contractions of the ventricles are caused on demand by inducing premature atrial contractions. In still other embodiments, a patient's vagus nerve is stimulated to simulate premature contractions of the ventricles. This abstract is not intended to be a complete description of, or limit the scope of, the invention.