ICD Shock Circuitry Current Limiting for Pulse Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing implantable cardioverter defibrillator (ICD) devices face challenges in efficiently producing different output pulses for inducing a fibrillation state and achieving defibrillation, while ensuring that the same shock generation circuitry does not interfere between these functions.
Innovation Solution
The implementation of a current limiting circuit within the shock generation circuitry of the ICD device, which is controllable by the processing circuitry to modulate the current flowing through it, allows for the production of output pulses with reduced voltage and power levels for inducing a fibrillation state without interfering with the production of defibrillation pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same shock generation circuitry is used for both inducing fibrillation and achieving defibrillation, then device complexity is reduced, but the reliability of producing different output pulses without interference is compromised
Solution Approach 1:
The shock generation circuitry is segmented into functional modules: energy storage device, current limiting circuit, and output circuit. The current limiting circuit is further divided into a first current limiting component and a second current limiting component, allowing independent control of current parameters for different pulse types (fibrillation induction vs. defibrillation), thus resolving the contradiction between using shared circuitry and maintaining reliable differentiated pulse production.
Solution Approach 2:
The patent introduces controllable current limiting components that can dynamically adjust their current limiting characteristics based on the required pulse type. The processing circuitry controls the current limiting circuit to provide different current limits during charging and discharging phases, enabling the same circuitry to reliably produce different output pulses for fibrillation induction and defibrillation without interference.
2Reliability
If high energy is delivered for defibrillation, then the effectiveness of terminating arrhythmia is improved, but the harmful impact on the patient increases
Solution Approach 1:
The patent applies different current limiting characteristics to different phases of the shock generation process. The first current limiting component provides a first current limit during energy storage charging, while the second current limiting component provides a second current limit during discharging. This allows optimized energy delivery for defibrillation effectiveness while controlling the harmful impact through appropriate current limiting.
Solution Approach 2:
The patent changes the current limiting parameters between different operational modes. By adjusting the current limit values in the current limiting circuit based on whether the device is charging or discharging, and whether inducing fibrillation or performing defibrillation, the system achieves effective defibrillation while minimizing harmful effects on the patient.
3Reliability
If current limiting is applied during energy storage charging, then the safety of the energy supply arrangement is improved, but the production efficiency of output pulses deteriorates
Solution Approach 1:
The current limiting circuit dynamically adjusts its limiting characteristics based on the operational phase. During charging of the energy storage device, the first current limiting component provides appropriate current limits for safety. During discharging to produce output pulses, the second current limiting component provides optimized current limits that maintain safety while maximizing pulse production efficiency. This dynamic adaptation resolves the contradiction between safety and efficiency.
Data Source
AI summary
An implantable cardioverter defibrillator device comprises a generator device having a processing circuitry and a shock generation circuitry, and at least one lead comprising a shock electrode for emitting an electrical output pulse. The shock generation circuitry comprises an energy supply arrangement containing at least one energy storage device for supplying energy to form an output pulse, an output circuit for outputting said output pulse to the shock electrode, and a current limiting circuit arranged electrically in between the energy supply arrangement and the output circuit such that a current supplied from the energy supply arrangement flows through the current limiting circuit towards the output circuit. The current limiting circuit comprises at least one current limiting component, wherein the current limiting circuit is controllable by the processing circuitry to modulate a current flowing through the current limiting circuit.