Adjustable Signal Window for P-Wave Detection in Leadless Pacing
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Solution Overview
Problem
Current leadless cardiac pacing devices face challenges in accurately sensing atrial activations due to the low signal amplitude of P-waves relative to other cardiac signal components, which complicates the timing of pacing therapy delivery.
Innovation Solution
A cardiac pacing system that includes a substernal or subcutaneous device sensing atrial activations from far-field vectors, determining desired signal features within a time-window, and adjusting the window to detect P-waves, allowing for precise triggering of pacing therapy delivery by a leadless pacing device positioned in the ventricle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If far-field sensing is used to detect atrial activations from a substernal or subcutaneous position, then device miniaturization and leadless configuration are achieved, but signal detection precision deteriorates due to low P-wave amplitude
Solution Approach 1:
The patent applies dynamics by making the signal evaluation window adjustable and movable along the cardiac cycle. The window can be dynamically repositioned to optimal locations where P-wave signals are most detectable, transforming a static sensing approach into a dynamic one that adapts to varying signal characteristics throughout the cardiac cycle
Solution Approach 2:
The patent changes the parameter of signal evaluation by adjusting the time-window position and duration. By modifying when and how long signals are evaluated within the cardiac cycle, the system optimizes detection of low-amplitude P-waves despite far-field sensing limitations
2Ease of operation
If signal evaluation window is fixed at standard positions, then device operation is simplified, but detection accuracy deteriorates when P-waves occur at variable timings
Solution Approach 1:
The signal evaluation window is made dynamic rather than fixed. The window can be repositioned along the cardiac cycle based on detected signal characteristics, allowing the system to adapt to variable P-wave timings while maintaining ease of operation through automated adjustment
Solution Approach 2:
The system uses feedback from continuous signal monitoring to determine optimal window positioning. By evaluating signal characteristics and adjusting the window position accordingly, the system creates a closed-loop detection mechanism that improves accuracy without complicating operation
3Measurement precision
If signal evaluation window size is increased to capture more signal features, then detection sensitivity improves, but response time deteriorates due to longer analysis duration
Solution Approach 1:
The signal evaluation window is made dynamic in both position and duration. Rather than using a consistently large window, the system adjusts the window size and position in real-time based on signal characteristics, allowing sensitive detection when needed while minimizing analysis time when signals are clear
Solution Approach 2:
The system performs preliminary signal evaluation to identify potential P-wave locations before committing to a full analysis. By pre-assessing signal characteristics and positioning the evaluation window strategically, the system reduces unnecessary analysis time while maintaining detection sensitivity
Data Source
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AI summary
A method and system that includes an implantable cardioverter defibrillator (ICD)determining signal characteristics of a cardiac signal within a signal evaluation window positioned along a first portion of a cardiac cycle and determining whether a P-wave occurs within the signal evaluation window associated with the first portion of the cardiac cycle. The signal evaluation window is adjusted to be positioned along a second portion of the cardiac cycle in response to the P-wave not occurring within the signal evaluation window and signal characteristics of the cardiac signal are determined within the adjusted signal evaluation window. A determination is made as to whether a P-wave occurs in response to the signal characteristics determined within the adjusted signal evaluation window, and the ICD delivers a trigger signal to a leadless pacing device instructing delivery of ventricular pacing therapy whenever a P-wave is determined to occur.