Multi-path Defibrillation via Impedance-Adaptive Waveforms
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Solution Overview
Problem
Current transthoracic defibrillation technologies, including biphasic waveforms and multiple-electrode systems, have a shock success rate of less than 70% for ventricular fibrillation, with remaining excitable gaps that can lead to refibrillation, due to inadequate current distribution and stimulation of myocardial tissue.
Innovation Solution
A transthoracic defibrillator system using three or more electrodes to establish multiple electrical paths across the thoracic cavity, with adjustable waveform parameters based on impedance distribution, delivering different defibrillation waveforms across each path to achieve a more uniform current density distribution and reduce excitable gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional single-path defibrillation is used, then the device complexity is low, but the defibrillation efficacy is insufficient with success rate less than 70%
Solution Approach 1:
The defibrillation system is segmented into multiple independent electrical paths, each with its own electrode pair. The defibrillator delivers defibrillation pulses through at least two different electrode pairs simultaneously or sequentially, creating multiple current vectors that traverse different portions of the heart. This segmentation allows broader and more uniform current distribution across the myocardium, improving defibrillation efficacy while managing system complexity through modular electrode design.
2Manufacturing precision
If multiple electrode systems are used to improve current distribution, then the current density uniformity improves, but the device complexity increases
Solution Approach 1:
Different electrode pairs are positioned to target specific regions of the heart, with each electrode pair creating a current vector optimized for its local anatomical region. The system adjusts waveform parameters independently for each electrical path based on local impedance characteristics, ensuring optimal current density distribution in each region. This local quality approach achieves uniform overall current distribution without requiring excessive electrodes throughout the entire system.
Solution Approach 2:
The defibrillator dynamically adjusts waveform parameters (amplitude, duration, shape) for each electrical path based on real-time impedance measurements and anatomical variations. The system can selectively activate different electrode pairs or combinations based on the detected arrhythmia type and patient anatomy, optimizing current distribution adaptively rather than using a fixed complex electrode configuration.
3Reliability
If high energy shocks are delivered to ensure depolarization, then the defibrillation capability improves, but the harmful effects such as tissue damage increase
Solution Approach 1:
The total defibrillation energy is segmented and distributed across multiple electrical paths rather than concentrated in a single high-energy shock. Each electrode pair delivers a lower energy pulse, but the combined effect of multiple paths achieves sufficient total current through the heart to depolarize myocardial tissue effectively. This segmentation reduces peak energy density at any single location, minimizing thermal and mechanical tissue damage while maintaining defibrillation capability.
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
The system improves defibrillation efficacy by reducing the areal extent of excitable gaps and enhancing current delivery to the heart, potentially increasing the success rate of defibrillation and reducing the risk of refibrillation.
Implementation Method 1
the defibrillator circuit has the capability to deliver a different defibrillation waveform across each of the at least two electrical paths
Data Source
AI summary
External electromagnetic stimulation of the interior of the body by applying three or more electrodes to the exterior of the patient to establish at least two electrical paths across the interior of the patient, determining impedance information representative of an impedance distribution across the interior of the body, delivering an electromagnetic waveform across each of the at least two electrical paths, wherein at least one parameter of the waveform is selected using the impedance information to produce a selected current density distribution at one or more locations within the interior of the body.