Ventricular Pacemaker Impedance Sensing for Atrial Event Detection
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Solution Overview
Problem
Existing implantable cardiac pacemakers struggle to reliably detect atrial events due to the low amplitude of atrial signals, particularly when positioned in the ventricle, leading to asynchronous ventricular pacing that can disrupt normal heart rhythm.
Innovation Solution
The use of an intraventricular impedance signal to detect atrial events directly or confirm atrial events sensed from other signals, enabling atrial-synchronized ventricular pacing without external sensors, using a leadless intracardiac pacemaker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a leadless intracardiac pacemaker is positioned in the ventricle for ventricular pacing, then the device can deliver ventricular pacing pulses, but the low amplitude of atrial signals makes reliable atrial event detection difficult
Solution Approach 1:
The patent uses an accelerometer as an intermediary device to detect atrial events. The accelerometer senses mechanical motion in the ventricle caused by atrial contractions, converting mechanical energy to electrical signals that can be processed to detect atrial events reliably, thereby solving the problem of low amplitude atrial signals when positioned in the ventricle
Solution Approach 2:
The patent replaces direct electrical signal detection with mechanical motion detection using an accelerometer. By sensing the mechanical motion in the ventricle that results from atrial contractions, the system overcomes the limitation of low amplitude electrical signals and enables reliable atrial event detection from a ventricular position
2Reliability
If atrial-synchronized ventricular pacing is implemented, then normal heart rhythm is maintained, but the device complexity increases due to additional sensing requirements
Solution Approach 1:
The patent makes the accelerometer serve multiple functions: it detects both ventricular events for ventricular pacing and atrial events for atrial-synchronized pacing. This multi-functionality enables the device to maintain normal heart rhythm through atrial-synchronized ventricular pacing without requiring separate sensing systems, thereby reducing overall device complexity while maintaining reliability
Solution Approach 2:
The accelerometer inherently provides the sensing capability needed for atrial-synchronized ventricular pacing by detecting mechanical motion from both atrial and ventricular events. The system processes this single mechanical signal to derive multiple pacing functions, allowing the device to serve itself with one sensor rather than requiring multiple specialized sensors
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 enhances the reliability and accuracy of atrial event sensing, ensuring ventricular pacing is synchronized with atrial contractions, thereby maintaining a more normal heart rhythm and improving hemodynamic benefits.
Implementation Method 1
The impedance sensing circuit is configured to produce an intraventricular impedance signal
Data Source
AI summary
An intracardiac ventricular pacemaker includes a pulse generator for delivering ventricular pacing pulses, an impedance sensing circuit, and a control circuit in communication with the pulse generator and the impedance sensing circuit. The pacemaker is configured to produce an intraventricular impedance signal, detect an atrial systolic event using the intraventricular impedance signal, set an atrioventricular pacing interval in response to detecting the atrial systolic event, and deliver a ventricular pacing pulse in response to the atrioventricular pacing interval expiring.