Virtual Sensing Vectors for Arrhythmia Discrimination
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Solution Overview
Problem
Current implantable cardioverter defibrillators (ICDs) face challenges in accurately distinguishing between shockable and non-shockable arrhythmias, leading to potential inappropriate therapy delivery due to limitations in sensing cardiac electrical signals.
Innovation Solution
The use of virtual cardiac electrical signal features computed from physical signals along predefined angles relative to physical sensing vectors allows for the discrimination between shockable and non-shockable arrhythmias by analyzing signal features and establishing criteria for confirming suspected conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If virtual sensing vectors are computed from physical sensing vectors, then arrhythmia detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent creates virtual sensing vectors as computational copies of physical sensing vectors by applying rotation matrices to the physical vector components. These virtual vectors replicate the electrical signal characteristics from alternative sensing angles without requiring additional physical electrodes, thereby improving detection accuracy while avoiding the complexity of implanting more electrodes.
Solution Approach 2:
The patent transforms the problem from a two-dimensional physical electrode arrangement to a multi-dimensional solution space by computing virtual sensing vectors at various angles (e.g., 45 degrees, 90 degrees) relative to the physical vectors. This dimensional expansion allows the device to analyze cardiac electrical activity from multiple virtual perspectives using the same physical hardware.
2Reliability
If multiple sensing vectors are used to differentiate arrhythmias, then reliability of therapy delivery is improved, but loss of energy increases
Solution Approach 1:
Instead of implanting multiple physical sensing electrodes which would require additional leads and increase energy consumption, the patent computationally generates virtual sensing vectors from the existing physical vector signals. This copying approach provides multiple sensing perspectives without the metabolic cost of additional hardware.
Solution Approach 2:
The patent makes the existing physical sensing electrodes serve multiple functions by using them to generate both direct physical vector signals and derived virtual vector signals. The same physical electrodes thus provide information for multiple sensing angles, reducing the need for additional energy-consuming components.
Data Source
AI summary
A medical device is configured to receive at least two physical cardiac electrical signals from a patient's heart via electrodes defining at least two physical sensing vectors. The medical device determines a signal feature for each of a plurality of virtual sensing vectors extending at a plurality of angles relative to one of the at least two physical sensing vectors during a known cardiac rhythm, compares the determined signal features and establishes criteria for confirming a suspected condition in response to the comparing.