ATP Train Pulse Count Based on Electrogram Propagation Time

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Solution Overview

Problem

Existing medical device systems delivering anti-tachyarrhythmia pacing (ATP) therapy face challenges in determining the optimal length of ATP trains, as predetermined lengths may be too long for some patients, potentially accelerating ventricular tachyarrhythmia into ventricular fibrillation, or too short, failing to terminate the arrhythmia and wasting therapeutic opportunities.

Innovation Solution

A method involving a medical device system that determines a first feature in a local electrogram and a second feature in a far-field electrogram to calculate a propagation time, thereby adjusting the number of pulses in an ATP train to achieve a desired propagation time, ensuring effective ATP delivery tailored to individual patients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a set predetermined length of ATP train is delivered to be therapeutic to a large number of patients, then the therapy can be applied broadly, but the ATP train may be too long for some patients (accelerating VT into VF) or too short for other patients (wasting therapeutic opportunities)

Engineering Contradiction:

Improveapplicability of ATP therapyVSAvoidefficacy of ATP therapy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic adjustment of ATP train length based on real-time measurement of conduction time. The system transitions from a fixed predetermined length to a variable length that adapts to each patient's specific physiology, particularly their ventricular conduction characteristics. This allows the therapy to be both broadly applicable and reliably effective for each individual patient.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of ATP train length based on measured conduction time. By measuring the time from pacing stimulus to ventricular activation and using this to determine the appropriate train length, the system optimizes therapy parameters for each patient, preventing both overtreatment (too long) and undertreatment (too short).

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a longer ATP train is delivered, then it may be more effective for patients with slower conduction, but it may accelerate ventricular tachyarrhythmia into ventricular fibrillation in patients with faster conduction

Engineering Contradiction:

Improveefficacy of ATP therapyVSAvoidrisk of accelerating VT into VF

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system uses feedback from measured conduction time to determine the appropriate ATP train length. By measuring the actual electrical conduction characteristics of the patient's heart and using this information to adjust the therapy, the system ensures the ATP train is long enough to be effective while short enough to avoid dangerous acceleration of arrhythmia.

Inventive Principle:

Principle #23Feedback

3Object-affected harmful factors

If a shorter ATP train is delivered, then it reduces the risk of accelerating VT into VF, but it may be too short to terminate the tachyarrhythmia and wastes therapeutic opportunities

Engineering Contradiction:

Improverisk of accelerating VT into VFVSAvoidefficacy of ATP therapy

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP4251263B1Guiding Anti-tachyarrhythmia pacing train design and electrode selection with electrograms

Publication Date: 2024.10.16 MEDTRONIC INC

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AI summary

An example medical device system includes therapy delivery circuitry configured to deliver anti-tachycardia pacing (ATP) therapy to a heart of a patient via electrodes communicatively coupled to the therapy delivery circuitry. The ATP therapy includes one or more ATP trains. The medical device system also includes processing circuitry configured determine a first propagation time based on a comparison of features in a local electrogram and a far-field electrogram, such as the time from a fiducial point in the local electrogram and QRS onset in the far-field electrogram. The processing circuitry is also configured to determine, based on the first propagation time, a number of pulses to achieve a second propagation time and control the therapy delivery circuitry to deliver the ATP train of at least the number of pulses.