Nanosecond Pulsed Electric Fields for Low-Energy Defibrillation
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Solution Overview
Problem
Current defibrillation methods often require high energy levels, leading to tissue damage, multiple shocks, and increased mortality, with existing biphasic waveforms offering only marginal improvements in reducing energy deposition and number of shocks.
Innovation Solution
The use of nanosecond pulsed electric fields (nsPEFs) for defibrillation, which reduce energy requirements by increasing shock amplitude while dramatically decreasing duration, utilizing displacement currents for deeper and more uniform tissue activation, and causing reversible cell membrane nanoelectroporation with smaller pore sizes, thereby minimizing tissue damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional defibrillation methods use high energy levels to terminate fibrillation, then defibrillation efficacy is improved, but tissue damage increases
Solution Approach 1:
The patent changes the temporal parameter of the defibrillation pulse from millisecond range to nanosecond range (10^-9 seconds), and adjusts the voltage amplitude accordingly. This parameter transformation allows achieving defibrillation efficacy through ultra-short high-voltage pulses that minimize energy deposition and thermal damage to cardiac tissue, resolving the contradiction between efficacy and tissue damage.
Solution Approach 2:
The patent employs periodic nanosecond pulsed electric fields delivered in controlled sequences. These periodic ultra-short pulses accumulate therapeutic effect while limiting total energy exposure, enabling reliable fibrillation termination without the collateral tissue damage associated with continuous or prolonged high-energy shocks.
2Object-affected harmful factors
If biphasic waveforms are used to reduce energy deposition, then tissue damage is reduced, but the number of shocks required increases
Solution Approach 1:
The patent transforms the pulse duration parameter from millisecond to nanosecond scale, which fundamentally changes the interaction mechanism with cardiac tissue. This ultra-short duration enables single-shock or minimal-shock defibrillation by creating transmembrane voltage gradients that directly terminate fibrillation without requiring multiple sequential shocks, thus reducing both time loss and treatment complexity.
Solution Approach 2:
The nanosecond pulses rush through the tissue extremely quickly, delivering the defibrillation effect in a single brief moment rather than through prolonged or repeated exposure. This 'rushing through' approach achieves termination in one or few shocks, skipping the need for multiple attempts required by conventional waveforms.
3Reliability
If multiple shocks are delivered to ensure defibrillation, then reliability is improved, but treatment time increases
Solution Approach 1:
By changing the pulse width to nanosecond duration and optimizing voltage amplitude, the patent achieves high defibrillation success rate in single or dual shocks. The ultra-short high-voltage pulses create sufficient transmembrane potential differences to reliably terminate fibrillation, eliminating the need for prolonged multi-shock protocols and reducing treatment time.
Solution Approach 2:
The nanosecond pulses deliver the complete defibrillation effect in advance through a single optimized shock, preventing the need for subsequent follow-up shocks. The preliminary ultra-short high-voltage pulse terminates fibrillation immediately, avoiding delays associated with sequential shock delivery.
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
NsPEF defibrillation achieves reliable termination of fibrillation with energies 10 times lower than conventional methods, reducing tissue damage and unnecessary shocks, while maintaining normal physiological heart activity without permanent changes in action potential duration or diastolic interval.
Implementation Method 1
nsPEFs induce transmembrane voltage using a different mechanism than conventional millisecond shocks. In these embodiments, the nsPEFs shock-induced transmembrane voltage is a result of displacement currents making a greater contribution to the membrane potential.
Implementation Method 2
nsPEFs interact with living matter using dielectric displacement, thereby allowing deeper penetration of the electric fields (e-fields) and more uniform activation of tissue.
Implementation Method 3
nsPEFs interact with living matter using dielectric displacement, thereby allowing deeper penetration of the electric fields (e-fields) and more uniform activation of tissue.
Data Source
AI summary
Methods for terminating fibrillation in a fibrillating heart employing nanosecond pulsed electric fields (nsPEFs) are disclosed. nsPEF defibrillation demonstrates its effectiveness as a new defibrillation modality, achieving reliable defibrillation with energies that are an order of magnitude lower than those needed for conventional defibrillation (millisecond shocks with mono- and bi-phasic waveforms). Tests did not reveal any negative effect of nsPEF defibrillation on cardiac tissue, in particular, cardiac tissue treated with nsPEFs does not exhibit a baseline shift in the optical transmembrane potential signal (distinctive feature that indicates electroporation), or changes in action potential duration or shape. The mechanism of nsPEF defibrillation is likely different from conventional defibrillation since it does not rely on membrane charging but on the basis of displacement currents that flow within nanoseconds after the shock is applied. nsPEFs provide the technology for the next generation of defibrillators that help emergency medical services to treat patients effectively.