Implantable Pacemaker Dynamic Pacing Algorithm
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Solution Overview
Problem
Traditional implantable medical devices for heart stimulation, such as cardiac pacemakers, often consume high power due to fixed safety margin algorithms in capture control features, which can lead to increased energy consumption and reduced device lifespan.
Innovation Solution
The proposed implantable medical device employs a dynamic algorithm that adjusts the pacing output based on the maximum capture threshold determined within either a longer or shorter time period, depending on the variance of capture thresholds, thereby optimizing power consumption while ensuring cardiac capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed safety margin algorithm is used to ensure cardiac capture, then patient safety is improved, but power consumption increases and device lifespan decreases
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed safety margin algorithm to a dynamic algorithm that continuously adapts the safety margin based on real-time capture threshold measurements. The safety margin is adjusted according to the variance observed in recent threshold measurements, allowing the system to maintain reliable cardiac capture while optimizing power consumption by reducing the margin when thresholds are stable.
Solution Approach 2:
The patent implements parameter changes by modifying the safety margin parameter based on statistical analysis of capture threshold measurements. The algorithm calculates the variance of threshold measurements over a defined period and dynamically adjusts the safety margin parameter accordingly, changing it from a fixed value to a variable that responds to physiological conditions, thereby resolving the contradiction between safety and power consumption.
2Reliability
If a higher pacing output is applied to ensure capture, then cardiac capture reliability is improved, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts the pacing output by calculating the variance of capture threshold measurements over time. When thresholds are stable (low variance), the pacing output is reduced to minimize energy consumption. When thresholds show high variability, the pacing output is increased to ensure reliable capture, thus dynamically optimizing the balance between capture reliability and energy loss.
Solution Approach 2:
The patent implements feedback by continuously measuring capture thresholds and using this information to adjust the pacing output. The algorithm monitors the variance of threshold measurements and feeds this information back to the pacing output adjustment mechanism, creating a closed-loop system that optimizes energy consumption while maintaining capture reliability based on real-time physiological feedback.
Data Source
AI summary
An implantable medical device for stimulating a heart, comprising a control unit, a memory unit, a stimulation unit for stimulating a cardiac region of a heart, and a detection unit for detecting an electrical signal of the heart. The memory unit comprises a computer-readable program that causes the control unit to perform the following steps: a) detecting capture thresholds during an observation period, each capture threshold detected in response to a sequence of pacing pulses delivered by the stimulation unit; b) storing the detected capture thresholds in the memory unit; c) determining threshold-to-threshold differences between two consecutive capture thresholds; and d) if a maximum determined threshold-to-threshold difference within the observation period is equal to or greater than a predetermined limit, adjusting a pacing output of the stimulation unit based on the maximum capture threshold determined within a first time period which is equal to or shorter than the observation period.