Pulse Generator Impedance Feedback for Cardiac Pacing
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Solution Overview
Problem
Pulse generators for cardiac applications face challenges in maintaining desired stimulation voltage or current due to variations in impedance, which can lead to ineffective cardiac stimulation therapy, especially post-cardiac surgery where precise impedance measurement and adjustment are crucial for secure fixation and easy removal of pacing wires.
Innovation Solution
An electrical pulse generator system that includes a display device and controller to show the relationship between applied electrical signals and measured impedance, allowing operators to adjust stimulation amplitude based on impedance readings, ensuring the impedance is within a recommended range for effective cardiac stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the impedance of the stimulation system varies outside the specified range, then the pacemaker cannot maintain the desired stimulation voltage or current, but providing real-time impedance measurement and display enables operators to adjust and maintain impedance within the specified range
Solution Approach 1:
The patent implements a feedback mechanism by measuring the actual impedance of the stimulation system and displaying it to the operator. This allows the operator to see the real-time impedance value and adjust the stimulation parameters accordingly to maintain the desired voltage or current within the specified range, thereby resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The patent replaces manual impedance estimation with automated electrical impedance measurement. By using electrical measurement techniques instead of mechanical or empirical methods, the system provides precise, real-time impedance data without adding significant mechanical complexity, thus improving reliability while minimizing the increase in device complexity.
2Adaptability or versatility
If pacing wires are manipulated to change their position or configuration, then the electrical properties of the stimulation system change, but this can affect the performance of the external pacemaker and jeopardize stimulation therapy
Solution Approach 1:
The patent provides real-time impedance measurement feedback that allows operators to monitor the electrical properties of the stimulation system as pacing wires are manipulated. This feedback enables operators to adjust wire configuration while maintaining stable impedance within the specified range, thus achieving adaptability without compromising pacemaker performance reliability.
Solution Approach 2:
The patent allows operators to perform preliminary impedance measurements before finalizing the pacing wire configuration. This preliminary action enables operators to predict and adjust for potential impedance changes before they occur, ensuring that the stimulation system remains within the specified impedance range and maintains reliable pacemaker performance.
3Stability of the object's composition
If the distal portion of the insulation including tines remains in place after wire attachment, then the wire fixation is secure, but the length and surface area of the bare wire increase, changing the electrical properties of the stimulation system
Solution Approach 1:
The patent implements impedance measurement feedback that allows operators to monitor the electrical properties of the stimulation system after wire attachment. This feedback enables operators to assess whether the remaining insulation and tines have caused unacceptable changes in impedance, allowing for precise control over the electrical properties while maintaining secure fixation.
Solution Approach 2:
The patent focuses on controlling the impedance parameter to ensure that the electrical properties of the stimulation system remain within the specified range. By monitoring impedance changes resulting from the presence of insulation and tines, the system allows operators to adjust parameters or configurations to maintain manufacturing precision in the electrical properties while preserving mechanical fixation stability.
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 enables precise impedance measurement and adjustment, reducing the risk of pacing failures by ensuring the impedance is within the specified range, thereby enhancing the effectiveness and safety of cardiac stimulation therapy.
Implementation Method 1
a controller which controls the display device to display an image showing the relationship between a first applied electrical signal, measured impedance, and a resulting electrical signal which varies depending on the first electrical signal and the measured impedance, according to Ohm's Law
Data Source
AI summary
An electrical pulse generator system such as a cardiac pacemaker or defibrillator system includes an impedance measuring device which measures the impedance across pacemaker leads, a display device, and a controller which controls the display device to display at least the measured impedance upon each stimulation pulse, or an image showing the relationship between a first applied electrical signal, measured impedance, and a resulting electrical signal which varies according to Ohm's Law. The system may include a short circuit detector and a pulse amplitude control module which switches between normal mode and safe mode operation based on short circuit detection, with different maximum stimulation pulse amplitudes in the normal and safe modes.