Implantable Medical Device Sensing Parameter Adjustment for MRI Interference
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Solution Overview
Problem
Implantable medical devices (IMDs) face interference from external sources like MRI devices, leading to incorrect sensing of cardiac signals due to induced currents or voltages, resulting in inappropriate therapy delivery or withholding of necessary therapy.
Innovation Solution
The IMD adjusts sensing parameters such as sampling frequency, resolution, gain, bandwidth, and filtering to obtain a more detailed representation of sensed signals, allowing for better separation of noise components from cardiac electrical signals, and employs signal processing techniques to reduce distortion caused by interfering signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the IMD uses standard sensing parameters, then the device operates normally under usual conditions, but the sensing accuracy deteriorates in the presence of interfering signals from external sources like MRI devices
Solution Approach 1:
The patent applies dynamics by making the sensing parameters adjustable and reconfigurable in response to detected interfering signals. The IMD dynamically changes sampling frequency, resolution, gain, bandwidth, and filtering parameters based on the presence of MRI or other external interference, allowing the system to adapt its sensing characteristics to maintain accuracy under varying conditions.
Solution Approach 2:
The patent directly implements parameter changes by modifying multiple sensing parameters simultaneously when interference is detected. These changes include increasing sampling frequency, increasing resolution, adjusting gain, expanding bandwidth, and modifying filtering characteristics. This comprehensive parameter adjustment allows the IMD to capture and process signals with enhanced detail, enabling accurate distinction between cardiac signals and interference.
2Measurement precision
If the IMD increases sampling frequency and resolution to capture detailed signal representation, then the ability to separate noise from cardiac signals improves, but the device complexity and processing requirements increase
Solution Approach 1:
The patent applies preliminary action by detecting the presence of interfering signals (such as MRI fields) before they severely degrade signal quality. Upon detecting the interfering environment, the IMD proactively adjusts its sensing parameters to enhanced settings, preparing the system to capture detailed signal representations before the interference completely overwhelms the cardiac signals.
Solution Approach 2:
The patent implements feedback by continuously monitoring the sensed signals for characteristics of interfering sources and using this information to dynamically adjust sensing parameters. The system processes the enhanced represented signals and uses the results to further refine parameter adjustments, creating a closed-loop system that maintains optimal sensing accuracy despite varying interference conditions.
3Reliability
If the IMD adjusts sensing parameters in response to detected interfering signals, then the reliability of cardiac signal sensing improves during MRI procedures, but the response time to adapt to new environments increases
Solution Approach 1:
The patent applies preliminary action by detecting the presence of interfering signals (such as MRI fields) before they severely degrade signal quality. Upon detecting the interfering environment, the IMD proactively adjusts its sensing parameters to enhanced settings, preparing the system to capture detailed signal representations before the interference completely overwhelms the cardiac signals.
Solution Approach 2:
The patent applies dynamics by making the sensing parameters adjustable and reconfigurable in response to detected interfering signals. The IMD dynamically changes sampling frequency, resolution, gain, bandwidth, and filtering parameters based on the presence of MRI or other external interference, allowing the system to adapt its sensing characteristics to maintain accuracy under varying conditions.
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
This approach enables IMDs to accurately sense cardiac signals even in the presence of interfering signals, ensuring appropriate therapy delivery and reducing the risk of oversensing or undersensing.
Implementation Method 1
the gradient magnetic fields or the RF fields may induce a current or voltage on the leads of the implantable medical system
Data Source
AI summary
An implantable medical device (IMD) adjusts a sensing configuration of a sensing module prior to or immediately subsequent to entering an environment having an external source that generates the interfering signal. The IMD may, for example, adjust a sampling frequency, resolution, input range, gain, bandwidth, filtering parameters, or a combination of these or other sensing parameters of the sensing module. These adjustments enable the sensing module to obtain a more detailed representation of the sensed signals, including the noise components of the sensed signals caused by the interfering signal. Without having an adequate representation of the noise components of the sensed signal, it is difficult to separate the noise components of the sensed signal from the cardiac electrical signal.