AV Node Refractory Period Extension for Ventricular Rate Stabilization

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current implantable cardiac devices struggle to stabilize the ventricular rate during episodes of atrial fibrillation without the need for ablation, as many patients are resistant to drug therapies and ablation methods are invasive.

Innovation Solution

An implantable cardiac stimulation device with sensing circuits and a pulse generator that delivers stimulation pulses to the AV node during an AV nodal refractory period, either directly or through neural stimulation to capture vagal innervations, to extend the AV nodal refractory period and stabilize the ventricular rate during atrial fibrillation episodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If drug therapy is used to stabilize ventricular rate during atrial fibrillation, then ventricular rate stabilization is improved, but patient resistance and treatment failure increase

Engineering Contradiction:

Improveventricular rate stabilizationVSAvoidpatient resistance to drug therapy

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces pharmacological intervention with an electrical/physical intervention. An implantable device delivers electrical stimulation to the AV node to extend its refractory period, substituting the chemical mechanism of drugs with an electrical mechanism that directly modifies cardiac conduction properties.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the refractory period parameter of the AV node through electrical stimulation. By applying electrical pulses during specific phases of the cardiac cycle, the device prolongs the AV nodal refractory period, thereby controlling ventricular rate response to atrial fibrillation without requiring pharmacological agents.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If ablation is used to stabilize ventricular rate during atrial fibrillation, then ventricular rate stabilization is improved, but invasiveness and procedural risk increase

Engineering Contradiction:

Improveventricular rate stabilizationVSAvoidinvasiveness of ablation procedure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Instead of destroying or ablating tissue to stop conduction, the patent uses electrical stimulation to modify conduction properties reversibly. The approach inverts the conventional ablation strategy by using excitatory stimulation during refractory periods to extend refractoriness, rather than using energy to destroy tissue and create permanent block.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The device utilizes the heart's own electrical system and refractory periods to achieve rate control. By timing stimulation pulses to occur during the AV nodal refractory period, the device leverages the natural electrophysiological properties of the heart to extend refractoriness and control ventricular rate without external surgical intervention.

Inventive Principle:

Principle #25Self-service

3Speed

If conventional pacing is used to maintain heart rate, then heart rate above limit is improved, but ventricular rate control during atrial fibrillation worsens

Engineering Contradiction:

Improveheart rate maintenanceVSAvoidventricular rate control during AF

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The device performs preliminary action by delivering stimulation pulses during the AV nodal refractory period, before atrial impulses can conduct to the ventricles. This preemptive stimulation extends the refractory period and prevents excessive ventricular rate response to atrial fibrillation, while still allowing normal pacing function when needed.

Inventive Principle:

Principle #10Preliminary action

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 effectively stabilizes the ventricular rate during atrial fibrillation episodes without ablation, maintaining normal conduction patterns in the ventricles and improving the quality of life for patients by reducing chaotic heart activity and associated symptoms.

Implementation Method 1

delivers a plurality of stimulation pulses to the AV node of the heart during an AV nodal refractory period

Methodology Applied

Scientific EffectElectrical stimulation: Electric Field

Data Source

PatentUS10888701B2Implantable cardiac stimulation device and method that stabilizes ventricular rate during episodes of atrial fibrillation

Publication Date: 2021.01.12 PACESETTER INC

AI summary

An implantable cardiac stimulation device provides electrical stimulation therapy to stabilize the ventricular rate of a heart during episodes of atrial fibrillation. The stimulation therapy may be a plurality of sub-threshold stimulation pulses delivered to capture AV node vagal innervations following the detection of atrial fibrillation.