Implantable Cardiac Sensing With Dynamic Windows for Atrial Events
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Solution Overview
Problem
Existing implantable medical devices face challenges in reliably sensing atrial events for ventricular pacing due to the small amplitude and noisy nature of atrial signals, which are often corrupted by ventricular signals, particularly when placed in the ventricle, leading to potential loss of atrioventricular synchrony.
Innovation Solution
An implantable medical device with a sensor arrangement and processing circuitry that dynamically sets an atrial detection window based on a start criterion, monitoring signal amplitude to ensure accurate detection of atrial events by starting the window only when ventricular signals have decayed, and employs separate processing channels for near-field and far-field signals to enhance signal differentiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the implantable medical device is placed in the ventricle to perform ventricular pacing, then the device can effectively pace the ventricle, but the atrial signals become small and noisy making reliable sensing difficult
Solution Approach 1:
The patent implements dynamic threshold adjustment where the sensing threshold is not fixed but adapts based on the detected signal characteristics and noise levels. The processing circuitry continuously monitors the atrial signal and adjusts the threshold dynamically to distinguish true atrial events from noise, thereby improving detection reliability while maintaining precision in the ventricular pacing context
Solution Approach 2:
The patent introduces an intermediary processing stage between signal acquisition and detection decision. The processing circuitry includes signal conditioning, filtering, and feature extraction components that act as intermediaries to enhance the atrial signal before final detection, allowing reliable sensing despite the small amplitude and noise when the device is placed in the ventricle
2Adaptability or versatility
If the device uses mechanical event detection (motion, sound, pressure) to sense atrial contractions, then it can detect atrial events, but the small signal amplitude makes detection difficult and signals are affected by external factors
Solution Approach 1:
The patent combines multiple sensing modalities (electrical, mechanical, pressure sensors) into a unified sensing system. By merging these different detection approaches, the device can cross-validate signals and improve reliability of atrial event detection, overcoming the limitations of small signal amplitude and external factor interference that affect individual modalities when the device is implanted in the ventricle
Solution Approach 2:
The processing circuitry implements feedback mechanisms where detected signals are analyzed and used to adjust subsequent detection parameters. The system provides feedback on signal quality and noise levels to dynamically adjust sensing sensitivity and filtering parameters, thereby maintaining reliable detection despite small amplitude signals and external disturbances in the ventricular implantation environment
Data Source
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AI summary
An implantable medical device (1) configured to provide for an intracardiac function comprises a body (10), a sensor arrangement arranged on the body (10) and configured to receive a cardiac sense signal (S2), and a processing circuitry (15) operatively connected to the sensor arrangement. The processing circuitry (15) is configured to process the cardiac sense signal (S2) received using the sensor arrangement to monitor the cardiac sense signal (S2) to detect whether a start criterion is fulfilled, wherein the start criterion is fulfilled if at least one signal sample (s(i-3)...s(i+3)) of the cardiac sense signal (S2) is smaller than a start threshold (TH), and to start an atrial detection window (Tsense) for detecting, within the atrial detection window (Tsense), a signal deflection of the cardiac sense signal (S2) potentially indicative of an atrial event (As), based on whether the detection criterion is fulfilled.