Automatic Pre-Excitation Interval Adjustment for Fusion Pacing

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Solution Overview

Problem

Existing cardiac resynchronization therapy (CRT) systems face challenges in efficiently delivering fusion-based therapy to patients with cardiac conduction abnormalities like left or right bundle branch block, due to varying conduction delays and electrode placement issues, leading to ineffective ventricular resynchronization.

Innovation Solution

The system automatically adjusts the AV interval to deliver a single ventricular pacing stimulus based on prior cardiac events, using a pre-excitation interval (PEI) calculated from intrinsic AV intervals, allowing for ventricular fusion and synchronization with minimal pacing energy, and can be adjusted dynamically based on patient physiologic state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single ventricular pacing stimulus is delivered to pre-excite the conduction-delayed ventricle, then ventricular resynchronization and stroke volume are enhanced, but the timing must be precisely optimized to fuse with intrinsic depolarization

Engineering Contradiction:
ImproveCRT delivery efficiencyVSAvoidpacing timing precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system calculates and prepares the optimal AV interval in advance based on prior cardiac events (A p/s -RVs and A p/s -LVs intervals), allowing the pacing stimulus to be delivered at the precise moment needed for fusion without requiring real-time complex calculations during each beat

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from sensed ventricular events (RVs, LVs) and prior cardiac cycles to continuously refine and adjust the AV interval, ensuring the pacing stimulus is delivered at the optimal moment for fusion while adapting to changing physiological conditions

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the AV interval is automatically adjusted based on prior cardiac events, then the need for manual echocardiographic evaluations is reduced, but the system complexity increases

Engineering Contradiction:
ImproveManual evaluation requirementVSAvoidAutomatic adjustment algorithm
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system performs self-optimization by automatically measuring prior cardiac intervals (A p/s -RVs, A p/s -LVs) and calculating the optimal AV interval without requiring external manual echocardiographic evaluations or clinical intervention

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical echocardiographic evaluation with an automated electronic system that uses electrical sensing and computational algorithms to determine the optimal pacing timing, substituting physical examination tools with digital signal processing

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Use of energy by moving object

If fusion-based CRT is delivered using intrinsic depolarization, then pacing energy is minimized, but the system must accurately distinguish between paced and intrinsic events

Engineering Contradiction:
ImprovePacing energy consumptionVSAvoidEvent differentiation accuracy
Core Design Contradiction:
Use of energy by moving objectVSDifficulty of detecting and measuring

Solution Approach 1:

The system uses feedback from ventricular sensing (RVs, LVs) to determine whether a ventricular event is paced or intrinsic, allowing the pacemaker to distinguish between the two and adjust timing accordingly to minimize energy consumption while maintaining accurate event differentiation

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2142249B1Apparatus for automatic determination of a fusion pacing pre-excitation interval
Publication Date: 2017.07.05 MEDTRONIC INC
  • EP2142249B1 patent drawingFigure 1
  • EP2142249B1 patent drawingFigure 2
  • EP2142249B1 patent drawingFigure 3

AI summary

Automated adjustment of a pre-excitation interval (PEI) used to deliver hemodynamically efficient fusion pacing therapy.