Implantable Device Stroke Ischemia Differentiation
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Solution Overview
Problem
Current implantable medical devices face challenges in accurately distinguishing between stroke and cardiac ischemia using electrocardiac signals, as changes indicative of stroke can also be caused by cardiac ischemia, leading to potential misinterpretation and delayed medical intervention.
Innovation Solution
An implantable medical device that senses electrocardiac signals and hemodynamic parameters to differentiate between stroke and cardiac ischemia by detecting preliminary indications of stroke based on IEGM or ECG changes and confirming or disconfirming them through hemodynamic parameter analysis, such as cardiac contractility and stroke volume, to deliver appropriate therapy and alerts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrocardiac signals are used to detect stroke, then stroke detection capability is improved, but misdiagnosis risk increases due to similarity with cardiac ischemia signals
Solution Approach 1:
The patent segments the diagnosis process into two distinct phases: preliminary stroke detection based on ECG/IEGM changes, and subsequent differentiation phase using hemodynamic parameters. This segmentation allows the system to first identify potential stroke cases and then reliably distinguish them from cardiac ischemia, resolving the contradiction between detection sensitivity and diagnostic reliability.
Solution Approach 2:
The patent introduces hemodynamic parameters as an intermediary measure to differentiate between stroke and cardiac ischemia. These parameters serve as a mediator that resolves the ambiguity created by similar electrocardiac signals, enabling reliable distinction between the two conditions while maintaining high stroke detection capability.
2Measurement precision
If additional hemodynamic sensors are added to distinguish stroke from cardiac ischemia, then diagnostic accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes existing implantable devices multi-functional by enabling them to perform both traditional cardiac monitoring and stroke detection/differentiation functions. By programming existing devices to analyze hemodynamic parameters for stroke-ischemia differentiation, the system achieves enhanced diagnostic accuracy without requiring entirely new specialized devices, thus limiting complexity increases.
Solution Approach 2:
The patent merges stroke detection and differentiation capabilities with existing cardiac rhythm management devices. By combining multiple functions (cardiac pacing, defibrillation, and stroke-ischemia differentiation) into a single integrated system, the patent achieves high diagnostic accuracy while avoiding the complexity of separate dedicated devices for each function.
Data Source
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AI summary
Techniques are provided for detecting and distinguishing stroke and cardiac ischemia within a patient using an implantable medical device. In one example, a preliminary indication of stroke is detected by a pacemaker or similar implantable device based on an analysis of features of an intracardiac electrogram (IEGM) sensed by the device. Exemplary IEGM features indicative of possible stroke include the onset of prominent U-waves, the onset of notched T-waves, and changes in ST segment duration or QT duration. Upon detection of a possible stroke, the device then detects one or more hemodynamic parameters that are typically affected by cardiac ischemia. Such hemodynamic parameters can include, e.g., cardiac contractility or stroke volume. The device then distinguishes stroke and cardiac ischemia from one another based on whether any changes detected in the hemodynamic parameters are consistent with cardiac ischemia. Implantable systems that exploit subcutaneous electrocardiograms (ECGs) rather than IEGMs are also described.