Optical Tissue Oxygenation Sensor for ICD Post-Shock Evaluation
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Solution Overview
Problem
Implantable cardioverter defibrillators (ICDs) face challenges in determining the success of shock therapy for arrhythmia treatment due to disruptions in intracardiac electrogram signals during shock delivery, leading to unnecessary repeat therapies and patient discomfort.
Innovation Solution
An optical sensor is used to monitor tissue oxygenation by measuring absolute tissue oxygen saturation and total hemoglobin volume fraction, providing evidence of successful arrhythmia therapy through improved tissue perfusion, independent of EGM signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ICD relies on EGM signal to determine shock therapy success, then device complexity is reduced, but measurement precision deteriorates due to signal disruption during shock delivery
Solution Approach 1:
The patent introduces an optical sensor as an intermediary measurement tool that indirectly assesses shock therapy success through tissue oxygenation levels. Instead of directly measuring electrical signals during shock delivery, the system uses light absorption properties of oxygenated and deoxygenated hemoglobin to determine hemodynamic recovery, thereby avoiding the signal disruption problem while maintaining diagnostic accuracy
Solution Approach 2:
The patent replaces the electrical measurement system (EGM signal analysis) with an optical measurement system. By substituting electrical field-based detection with optical field-based detection using light sources and photodetectors, the system eliminates interference from electrical shocks and provides reliable post-shock evaluation through tissue oxygenation measurements
2Reliability
If ICD delivers repeat shock therapy due to delayed rhythm detection, then reliability of arrhythmia treatment is improved, but use of energy deteriorates due to unnecessary shock deliveries
Solution Approach 1:
The patent implements a feedback mechanism where tissue oxygenation measurements are continuously monitored after shock delivery to determine whether the arrhythmia has been successfully converted. This feedback loop allows the ICD to make informed decisions about repeat shock delivery based on actual hemodynamic recovery status rather than relying solely on delayed EGM signal analysis, thereby reducing unnecessary energy consumption from futile repeat shocks
Solution Approach 2:
The patent performs preliminary assessment of shock therapy success by measuring tissue oxygenation changes immediately after shock delivery, before the ICD would traditionally wait for delayed EGM signal clearance. This preliminary action provides early indication of therapeutic efficacy, enabling timely and accurate decisions about whether repeat shock therapy is necessary, thus optimizing energy usage
3Reliability
If ICD delivers repeat shock therapy due to signal disruption, then reliability of treatment is improved, but patient comfort deteriorates due to painful repeated shocks
Solution Approach 1:
The patent uses real-time feedback from optical tissue oxygenation measurements to accurately determine shock therapy success, eliminating the need for delayed EGM signal-based assessment. This allows the ICD to confidently avoid unnecessary repeat shock deliveries, thereby maintaining treatment reliability while significantly improving patient comfort by preventing painful and unnecessary repeated shocks
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 allows for accurate detection of arrhythmia therapy success, reducing unnecessary shock deliveries, minimizing patient discomfort, and conserving battery charge by using tissue oxygenation measurements to assess hemodynamic recovery.
Implementation Method 1
an optical sensor is used to monitor tissue oxygenation by measuring absolute tissue oxygen saturation and total hemoglobin volume fraction
Data Source
AI summary
A method and device for delivering therapy that includes an electrode to sense cardiac signals and to deliver a therapy, a monitoring module detecting a cardiac event in response to the sensed cardiac signals using first detection criteria, a sensor emitting light and detecting emitted light scattered by a tissue volume adjacent the sensor to generate a corresponding detected light intensity output signal, a control module coupled to the sensor to control light emission of the sensor in response to delivering the therapy, and a controller coupled to the monitoring module, the therapy delivery module and the sensor, the controller configured to determine tissue oxygenation measurements in response to the output signal, determine a tissue oxygenation trend in response to the tissue oxygenation measurements, determine a recovery index in response to the determined tissue oxygenation trend, and control one or both of detecting a cardiac event by the monitoring module and delivery of therapy by the therapy delivery module in response to the determined recovery index.