Implantable Optical Sensing for Non-Barometric Arrhythmia Assessment
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Solution Overview
Problem
Current implantable cardioverter/defibrillators (ICDs) rely solely on electrocardiogram-based technology for delivering shocks, leading to inappropriate and premature shocks due to misinterpretation of cardiac arrhythmias, as they cannot assess hemodynamic stability during arrhythmias, and existing pressure-sensing technologies fail due to tissue fibrosis encasement.
Innovation Solution
The use of non-barometric signals, such as optical, electrical, thermal, and ultrasound signals, to determine hemodynamic stability by sensing mechanical movements of the heart through optical fibers and ultrasound transceivers, combined with electrocardiographic signals, to accurately assess the need for ICD shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ICDs rely solely on electrocardiogram-based technology for detecting arrhythmias, then the device complexity is reduced and ease of operation is improved, but inappropriate and premature shocks occur due to inability to assess hemodynamic stability
Solution Approach 1:
The patent combines electrocardiogram-based arrhythmia detection with mechanical movement sensing (accelerometers, gyroscopes) and barometric pressure sensing into a unified decision-making system. This multi-sensor integration allows the ICD to simultaneously monitor electrical cardiac activity and hemodynamic status, resolving the contradiction by merging multiple sensing modalities to achieve both reliability and informed decision-making without excessive complexity
Solution Approach 2:
The patent introduces barometric pressure sensing as an intermediary mechanism to assess hemodynamic stability during arrhythmias. The barometric sensor acts as a mediator that provides indirect information about cardiac output and hemodynamic status without requiring direct intracardiac pressure measurement, thereby improving reliability while maintaining acceptable device complexity
2Measurement precision
If pressure-sensing technologies are used to assess hemodynamic stability, then measurement precision is improved, but the sensor becomes useless over time due to tissue fibrosis encasement
Solution Approach 1:
The patent replaces mechanical pressure sensors (which are encased by tissue fibrosis) with barometric pressure sensing and mechanical movement sensing technologies. These alternative sensing methods do not require direct contact with cardiac pressure environments, thereby avoiding the fibrosis encasement problem while maintaining measurement precision for hemodynamic assessment
Solution Approach 2:
The patent uses barometric pressure as an intermediary measurement approach. Instead of directly measuring intracardiac pressure with vulnerable sensors, the system uses ambient barometric pressure changes in conjunction with mechanical movement data to infer hemodynamic status, thereby extending sensor lifespan while maintaining measurement precision
3Speed
If ICDs deliver shocks based on preset duration without hemodynamic assessment, then the response time is reduced and productivity is improved, but premature shocks occur when patients are still hemodynamically stable
Solution Approach 1:
The patent performs preliminary hemodynamic assessment using barometric sensing and mechanical movement detection immediately upon detecting an arrhythmia, before committing to shock delivery. This preliminary evaluation of hemodynamic stability allows the system to rapidly determine whether shock is appropriate, maintaining fast response speed while preventing premature shocks in hemodynamically stable patients
Solution Approach 2:
The patent implements feedback mechanisms where continuous monitoring of barometric pressure and mechanical movement provides real-time information about hemodynamic status during arrhythmia. This feedback loop enables dynamic decision-making, allowing the system to adjust shock delivery timing based on actual hemodynamic response, thereby improving reliability while maintaining rapid response capability
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 significantly reduces inappropriate and premature ICD shocks by ensuring shocks are delivered only when the patient is hemodynamically unstable, thereby minimizing discomfort and morbidity.
Implementation Method 1
transmitting an optical signal via at least one optical fiber in a set of one or more optical fibers disposed in a heart of the subject... receiving a reflected portion of the optical signal via the at least one optical fiber, wherein changes in at least one parameter of the received reflected portion of the optical signal are indicative of the mechanical movement of the heart
Implementation Method 2
transmitting, using an ultrasound emitter, an ultrasound signal towards at least one anatomic reference structure within a heart of the subject over a given time period; receiving, using an ultrasound receiver, a reflected portion of the ultrasound signal over the given time period
Data Source
AI summary
Certain aspects of the present disclosure provide methods, apparatus, and computer-readable media for determining hemodynamic stability in a subject. In one example method, an optical signal is transmitted via at least one optical fiber in a set of one or more optical fibers partially disposed in a heart of the subject, wherein the at least one optical fiber in the set is configured to bend with the mechanical movement of the heart. A reflected portion of the optical signal is received via the at least one optical fiber, wherein changes in at least one parameter of the received reflected portion of the optical signal are indicative of the mechanical movement of the heart. A hemodynamic stability of the heart is determined based on the received reflected portion. Hemodynamic stability of the subject may further be determined based on thermal, ultrasound, and/or impedance signals measured in or near the heart.