IMD Pacing Optimization for Battery Longevity
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Solution Overview
Problem
Leadless pacemakers (LPs) and other implantable medical devices (IMDs) face challenges in prolonging device longevity due to limited battery life, necessitating reduced battery current drain.
Innovation Solution
The method involves determining pacing impedance and capture thresholds to estimate maximum membrane response, then using this information to create an iso-safety factor strength duration curve and a current or charge drain curve, ultimately identifying a preferred pacing parameter set that minimizes current drain while maintaining safety margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pacing amplitude is increased to ensure capture safety margin, then reliability of pacing is improved, but current drain increases reducing device longevity
Solution Approach 1:
The patent applies parameter changes by determining optimal pulse width values that minimize current drain while maintaining adequate capture thresholds. The system calculates pacing parameters (pulse width, amplitude) based on measured tissue impedance and capture threshold, adjusting these parameters dynamically to achieve the lowest possible current drain that still ensures reliable capture with appropriate safety margins.
Solution Approach 2:
The system dynamically adjusts pacing parameters based on real-time measurements of tissue impedance and capture threshold. Rather than using fixed parameters, the device continuously optimizes pulse width and amplitude based on actual tissue response, allowing the pacing parameters to adapt to changing tissue conditions while minimizing current drain throughout the device lifespan.
2Duration of action of stationary object
If pulse width is reduced to lower current drain, then device longevity is improved, but capture threshold increases reducing reliability
Solution Approach 1:
The patent determines optimal pulse width values by analyzing the relationship between pulse width, amplitude, and current drain. The system calculates the minimum effective pulse width required to achieve capture at the determined amplitude, then uses this information to select pulse width values that minimize current drain while maintaining adequate capture thresholds through coordinated parameter adjustment.
Solution Approach 2:
The system dynamically optimizes pulse width based on real-time tissue impedance measurements and capture threshold determinations. The device adjusts pulse width dynamically to match the minimum effective width required for capture at the current amplitude setting, preventing both excessive current drain from overly long pulses and insufficient capture from overly short pulses.
3Duration of action of stationary object
If pacing amplitude is reduced to lower current drain, then device longevity is improved, but capture threshold increases reducing reliability
Solution Approach 1:
The patent determines optimal pacing amplitudes by measuring tissue impedance and capture threshold, then calculating the minimum amplitude required for reliable capture. The system uses this information to set amplitude values that minimize current drain while ensuring adequate capture, adjusting amplitude dynamically based on actual tissue response rather than using fixed high amplitude values.
Solution Approach 2:
The system incorporates feedback from capture threshold measurements and tissue impedance determinations to continuously optimize pacing amplitude. The device uses feedback from capturing responses to verify that the determined amplitude provides adequate capture margin, then adjusts amplitude accordingly to minimize current drain while maintaining reliability through closed-loop optimization.
Data Source
AI summary
Disclosed herein are methods for use with an IMD configured to deliver pacing pulses to cardiac tissue, and related systems for use with and/or including an IMD. A method includes determining a pacing impedance of the cardiac tissue, a first capture threshold of the cardiac tissue, and an estimate of a maximum membrane response for the cardiac tissue. Additionally, the method includes using the maximum membrane response to determine an iso-safety factor strength duration curve. The method also includes determining a current or charge drain curve, and determining, based on the iso-safety factor strength duration curve and the current or charge drain curve, a preferred pacing parameter set that includes a preferred pulse width and a preferred pacing amplitude, which provides a specified safety margin.