Extravascular Arrhythmia Induction via Subcutaneous Electrodes
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Solution Overview
Problem
Current medical devices, particularly implantable cardioverter-defibrillators (ICDs), rely on intravascular electrodes to induce arrhythmia for defibrillation threshold testing, which can be invasive and may not be feasible in subcutaneous ICD systems lacking intravascular leads, necessitating an alternative method for arrhythmia induction.
Innovation Solution
The use of extravascular electrodes, such as subcutaneous or external electrodes, to deliver electrical stimulation pulses, including pacing and shock pulses, to induce arrhythmia in the heart, either through a subcutaneous ICD system or an external device, allowing for arrhythmia induction without the need for intravascular leads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If intravascular electrodes are used to induce arrhythmia, then arrhythmia induction is achieved, but the procedure becomes invasive and may not be feasible in subcutaneous ICD systems
Solution Approach 1:
The patent extracts the arrhythmia induction function from the intravascular lead system and relocates it to an extravascular electrode system. The extrathoracic electrode and subcutaneous electrode can be placed on the patient's body surface without requiring intravascular leads, thereby eliminating the invasive aspect while maintaining the ability to induce arrhythmia for defibrillation threshold testing.
Solution Approach 2:
The patent introduces an external defibrillator as an intermediary device that works in conjunction with the extravascular electrodes to induce arrhythmia. This external device serves as a mediator that provides the necessary electrical stimulation without requiring the ICD itself to have intravascular leads, enabling arrhythmia induction in subcutaneous ICD systems.
2Reliability
If arrhythmia induction is performed using the ICD's energy storage module, then arrhythmia induction is achieved, but the battery life of the ICD is reduced
Solution Approach 1:
The patent segments the energy storage function by separating the arrhythmia induction energy requirement from the ICD's battery. The external defibrillator is equipped with its own energy storage module that is dedicated to providing power for arrhythmia induction and defibrillation shocks, while the ICD's battery continues to power only the implantable monitoring and pacing functions, thereby preserving ICD battery life.
Solution Approach 2:
The external defibrillator acts as an intermediary energy source for arrhythmia induction. By using the external device's energy storage module rather than the ICD's battery, the system allows arrhythmia induction to be performed without depleting the ICD's power supply, thus extending the operational duration of the implanted device.
3Ease of operation
If electrical stimulation is delivered via extravascular electrodes, then arrhythmia induction is achieved without intravascular leads, but more energy is required to induce arrhythmia
Solution Approach 1:
The external defibrillator serves as an intermediary device that is specifically designed to handle the higher energy requirements of extravascular arrhythmia induction. This external device has its own energy storage module capable of storing and delivering the necessary energy levels to induce arrhythmia through extravascular electrodes, thereby accommodating the increased energy demand without compromising the ICD's capabilities.
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 enables arrhythmia induction in patients with subcutaneous ICD systems, prolongs battery life by shifting the energy requirement to external devices, and minimizes patient discomfort by limiting skeletal muscle contractions, thus providing a viable alternative for defibrillation threshold testing.
Implementation Method 1
a therapy module comprising an energy storage module, and a processor that is configured to control the therapy module to discharge the energy storage module to generate a cardiac pacing pulse
Implementation Method 2
delivering electrical stimulation via an extravascular electrode... the shock pulse is configured to induce an arrhythmia in the heart of the patient
Data Source
Figure 1A
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Figure 1C
AI summary
A cardiac arrhythmia may be induced by delivering a sequence of pulses to a patient via one or more extravascular electrodes. In one example, one or more pacing pulses may be delivered to a patient via an extravascular electrode and a shock pulse may be delivered to the patient the extravascular electrode. In some examples, the pacing pulses and the shock pulse may be generated with energy from a common energy storage module and without interim charging of the module. For example, the pacing and shock pulses may be generated as the energy storage module dissipates. In another example, a cardiac arrhythmia may be induced in a patient by delivering a burst of pulses to a patient via an extravascular electrode. In some cases, the burst of pulses may be generated with energy from a common energy storage module and without interim charging of the energy storage module.