Cardiac Pacing Device AV Delay Adjustment

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Solution Overview

Problem

Current cardiac pacing therapies face challenges in optimizing pacing parameters, such as AV delay, to ensure effective synchronization and prevent pseudo-fusion or delayed activation, especially under ambulatory conditions, where mechanical responses may deviate from optimal electro-mechanical intervals.

Innovation Solution

A system combining an ECG belt and an implantable medical device that determines optimal pacing parameters based on electrical heterogeneity metrics during device placement, and continuously adjusts pacing settings, like AV delay, to maintain an optimal electro-mechanical response interval by sensing mechanical responses via an accelerometer, thereby ensuring synchronized pacing therapy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fixed pacing parameters are used during ambulatory pacing, then device operation is simple, but optimal synchronization is lost due to changes in electro-mechanical response interval

Engineering Contradiction:
Improvesynchronization effectivenessVSAvoidpacing delivery system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pacing system dynamically adjusts the AV delay parameter based on real-time monitoring of the electro-mechanical response interval. The system transitions from fixed parameter operation to adaptive parameter modification, allowing the pacemaker to optimize synchronization effectiveness by changing pacing parameters in response to varying physiological conditions during ambulatory activity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements a feedback mechanism where the pacemaker monitors the electro-mechanical response interval (time from pacing stimulus to mechanical contraction) and uses this information to adjust the AV delay parameter. This closed-loop control ensures that pacing parameters remain optimized for effective synchronization even as physiological conditions change during ambulatory activity.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If AV delay is shortened to prevent pseudo-fusion, then mechanical response timing improves, but cell-to-cell conduction may be delayed

Engineering Contradiction:
Improvemechanical response timingVSAvoidcell-to-cell conduction time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system dynamically modifies the AV delay parameter based on monitored electro-mechanical response intervals. By adjusting this timing parameter in real-time, the system optimizes the balance between preventing pseudo-fusion (ensuring mechanical response occurs at appropriate time) and allowing sufficient cell-to-cell conduction time for effective cardiac activation.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for real-time adjustment of pacing parameters to maintain optimal synchronization patterns, preventing pseudo-fusion and delayed activation, even under ambulatory conditions, by monitoring and adjusting AV delay settings to align with the optimal electro-mechanical response interval.

Implementation Method 1

sensing an EM signal from an EM sensor of the pacing device; The mechanical response may be measured at the peak of an accelerometer signal

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

sensing electrical activity of tissue of a patient from a plurality of external electrodes during the delivered non-ambulatory pacing therapy

Methodology Applied
Scientific EffectElectrical activity sensing: Electric Field

Data Source

PatentEP3758794B1Delivery of pacing therapy by a cardiac pacing device
Publication Date: 2023.03.29 MEDTRONIC INC
  • EP3758794B1 patent drawingFigure 1
  • EP3758794B1 patent drawingFigure 2
  • EP3758794B1 patent drawingFigure 3

AI summary

A method and system for delivering cardiac pacing therapy that includes sensing electrical activity of tissue of a patient from a plurality of external electrodes during delivery of a non-ambulatory pacing therapy from a pacing device and determining an optimal electromechanical (EM) response time from an optimal electrical activation determined from electrical heterogeneity information obtained during non-ambulatory pacing therapy. During delivery of subsequent ambulatory pacing, the pacing sensing an EM signal from an EM sensor of the pacing device, determines a current EM response time in response to the sensed EM signal, and adjusting a pacing parameter setting of the ambulatory pacing therapy in response to comparing the current EM response time to the optimal EM response time.