Pulsed Field Ablation Spasm Mapping for Phrenic Nerve Protection
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Solution Overview
Problem
Pulsed Field Ablation (PFA) treatments can cause nerve stimulation, leading to muscle spasm and potential nerve damage, particularly affecting the phrenic nerve, resulting in discomfort and risk of irreversible damage during cardiac ablation procedures.
Innovation Solution
A system and method for monitoring muscle spasm during PFA using motion sensors to create a spatial spasm map and provide real-time guidance to avoid or reduce nerve stimulation, including automatic adjustments to PFA parameters to prevent irreversible nerve damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PFA electrical pulses are delivered to ablate cardiac tissue, then ablation efficacy is improved, but nerve stimulation and muscle spasm occur
Solution Approach 1:
The system performs preliminary spasm mapping by delivering test pacing signals to multiple tissue locations before actual ablation to identify regions likely to cause muscle spasm. This advance identification allows the physician to plan an ablation strategy that avoids high-risk areas or uses lower energy settings in those regions, thereby preventing nerve stimulation and muscle spasm while maintaining ablation efficacy in safe zones
Solution Approach 2:
The system provides real-time feedback during ablation by monitoring for muscle spasm responses and dynamically adjusting ablation parameters. When spasm is detected or anticipated based on the spasm map, the system can automatically reduce power, pause delivery, or redirect ablation to alternative locations, creating a closed-loop control system that balances ablation effectiveness with nerve protection
2Productivity
If PFA pulse energy is increased to improve ablation, then ablation speed increases, but risk of irreversible nerve damage increases
Solution Approach 1:
The system applies different energy levels and ablation strategies to different tissue locations based on their individual spasm risk characteristics. High-energy rapid ablation is applied to low-risk areas to maintain productivity, while reduced energy or slower ablation is used in high-risk areas identified through spasm mapping, creating a spatially varying ablation approach that optimizes both speed and safety
Solution Approach 2:
The system may deliver slightly lower than maximum recommended energy levels in high-risk regions to prevent nerve damage, accepting partial reduction in ablation efficiency in those specific areas while maintaining overall treatment effectiveness. This selective reduction in energy application prevents irreversible damage while preserving productivity in safer zones
3Reliability
If spasm monitoring and mapping systems are implemented, then nerve damage risk is reduced, but device complexity increases
Solution Approach 1:
The system utilizes the patient's own physiological response (muscle spasm) as the monitoring mechanism, eliminating the need for separate complex sensors or imaging systems. The spasm mapping is performed using the same pacing and sensing capabilities already present in standard ablation systems, allowing the existing equipment to serve dual purposes of treatment and safety monitoring without adding substantial complexity
Solution Approach 2:
The ablation system's existing pacing and electrical field generation capabilities are used for multiple functions: delivering therapeutic ablation pulses, performing spasm mapping, and guiding safe ablation planning. This multi-functionality allows the system to provide comprehensive nerve protection without requiring dedicated separate monitoring hardware, thereby limiting the increase in device complexity
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
Reduces muscle spasm and minimizes the risk of nerve damage by providing real-time spasm monitoring and guidance, allowing for safer and more effective PFA treatments.
Implementation Method 1
providing motion signals indicative of motion of at least one region of a patient's tissue
Implementation Method 2
Pulsed Field Ablation (PFA), in which Irreversible electroporation (IRE) is applied via short electrical pulses referred to in the following electrical PFA pulses, that generate high enough electrical fields (typically greater than 450 Volts per centimeter) to irreversibly damage the cells
Implementation Method 3
processing motion signals obtained from the at least one motion sensor during a PFA treatment
Data Source
AI summary
Systems and methods to process motion signals obtained from at least one motion sensor during delivery of plurality of PFA pulses or pacing signals to heart tissue location(s) and determine degrees of diaphragm spasm affected by the PFA or pacing signals. In some embodiments the system identifies reduction of diaphragm spasm during delivery of PFA pulses to a certain location and upon such identification indicates that continued delivery of further PFA pulses to that certain location may cause irreversible damage to the Phrenic nerve. Additionally, or alternatively, the system utilizes the diaphragm spasm degrees measured following pacing or ablation of at least two heart tissue locations, to map the degrees of spasm affected by the ablation of various heart tissue locations and thereby enables to conduct ablation at location associated with reduced spasm.