Optical Perfusion Sensor Control for Cardiac Signal Monitoring
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Solution Overview
Problem
Implantable cardiac monitors struggle to accurately diagnose syncope events, as they often occur infrequently and have sudden onset, making it difficult to determine whether they are related to cardiac arrhythmias or other factors like low blood pressure.
Innovation Solution
An implantable medical device (IMD) equipped with an optical perfusion sensor that monitors blood oxygen saturation levels, allowing for the detection of changes in blood oxygen saturation and perfusion values, which can indicate cardiac arrhythmias or other conditions contributing to syncope, and adjusts the operation of the cardiac signal sensing module accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If implantable cardiac monitors continuously monitor cardiac signals to capture infrequent syncope events, then the reliability of diagnosis is improved, but the energy consumption increases
Solution Approach 1:
The patent implements periodic monitoring of cardiac signals at predetermined time intervals rather than continuous monitoring. The IMD is configured to sense cardiac signals periodically, which reduces energy consumption while still capturing syncope events over the long-term monitoring period. This periodic action allows the device to balance between diagnostic reliability and power conservation.
Solution Approach 2:
The patent employs preliminary detection of cardiac arrhythmias as a trigger condition before initiating more intensive monitoring or therapy. The IMD first detects cardiac arrhythmias, and only when these are detected does it proceed to monitor perfusion values and activate therapy. This preliminary action filters out unnecessary monitoring during normal conditions, reducing overall energy consumption while maintaining diagnostic reliability for relevant events.
2Measurement precision
If the IMD monitors both cardiac signals and perfusion values simultaneously to differentiate syncope causes, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent integrates multiple sensing functions into a single implantable medical device that can monitor both cardiac signals and perfusion values. The IMD is configured to sense cardiac signals, detect cardiac arrhythmias, and monitor perfusion values related to blood flow. This multi-functionality allows simultaneous monitoring of multiple parameters to accurately differentiate syncope causes without requiring separate devices, thereby managing complexity while improving measurement precision.
Solution Approach 2:
The patent uses feedback mechanisms where the detection of cardiac arrhythmias triggers subsequent monitoring of perfusion values. When a cardiac arrhythmia is detected, the system activates perfusion monitoring to determine if the arrhythmia caused syncope. This feedback-based approach allows the system to dynamically adjust monitoring based on detected conditions, improving diagnostic accuracy while managing complexity by only activating full monitoring when necessary.
3Measurement precision
If the optical perfusion sensor operates continuously to detect blood oxygen saturation changes, then the measurement precision is improved, but the use of energy increases
Solution Approach 1:
The optical perfusion sensor operates periodically rather than continuously, measuring blood oxygen saturation at predetermined time intervals. The IMD is configured to monitor perfusion values periodically, which reduces energy consumption of the optical sensor while still capturing meaningful changes in blood oxygen saturation over time. This periodic operation maintains measurement precision for detecting syncope-related changes while conserving energy.
Solution Approach 2:
The system performs preliminary detection of cardiac arrhythmias before activating intensive perfusion monitoring. Only when a cardiac arrhythmia is detected does the system activate the optical perfusion sensor to monitor blood oxygen saturation levels. This preliminary action ensures that the energy-intensive perfusion monitoring is only activated when potentially relevant events occur, maintaining measurement precision for critical events while minimizing overall energy consumption.
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
Enables the IMD to effectively monitor and store cardiac signals corresponding to changes in blood oxygen saturation, providing clinicians with valuable insights into the physiological conditions surrounding syncope events, helping to differentiate between arrhythmia-related and non-arrhythmia-related causes.
Implementation Method 1
a detector that senses light that was emitted by the light source and transmitted through the blood-perfused tissue or reflected by a blood mass
Implementation Method 2
The detector may generate an electrical signal that indicates an amount (or intensity) of light absorbed and/or reflected by a blood mass within the blood-perfused tissue, from which the blood oxygen saturation level may be determined
Data Source
AI summary
An optical perfusion sensor may monitor blood oxygen saturation of blood-perfused tissue, which may be referred to as tissue perfusion, until a tissue perfusion value is within a threshold range of a reference value, and, in some examples, for at least a minimum period of time. The tissue perfusion value may indicate an absolute blood oxygen saturation level or a relative change in blood oxygen saturation level. The reference value may be, for example, determined by an optical oxygenation (O2) variation index that indicates a change in blood oxygen saturation of tissue. In some examples, an operation of a cardiac signal sensing module may be controlled based upon detecting a threshold change in tissue perfusion. For example, the cardiac signal sensing module may be activated upon detecting a threshold change in tissue perfusion.