Implantable Device Ventricular Pacing via Mechanical Activity Detection
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Solution Overview
Problem
Implantable medical devices struggle to detect ventricular activity during antitachycardia atrial pacing therapy due to masked electrical detection by atrial post-stimulation refractory periods, leading to a risk of triggering ventricular arrhythmias with asynchronous pacing.
Innovation Solution
Incorporating an endocardial acceleration sensor to detect mechanical activity of the ventricle, allowing for controlled and synchronous antibradycardia pacing by using a mechanical activity signal representative of ventricular contractions, which supplements or replaces electrical activity detection during therapy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical detection is used during antitachycardia atrial pacing, then the detection system is simple, but ventricular activity cannot be detected due to masked electrical detection by atrial post-stimulation refractory periods
Solution Approach 1:
The patent introduces an accelerometer sensor as an intermediary detection means to detect ventricular mechanical activity when electrical detection is blocked by atrial refractory periods. The accelerometer serves as a mediator that provides alternative ventricular activity information through mechanical motion detection, bypassing the electrical detection blockage caused by post-atrial pacing refractory periods.
2Reliability
If asynchronous ventricular pacing is applied during antitachycardia atrial pacing, then ventricular pauses are treated, but there is a risk of triggering ventricular arrhythmias
Solution Approach 1:
The patent implements feedback control by continuously monitoring ventricular mechanical activity through the accelerometer and adjusting pacing timing accordingly. The detected mechanical activity signals provide feedback about actual ventricular contraction status, enabling the system to synchronize pacing delivery with the ventricular cycle and avoid triggering arrhythmias while still managing ventricular pauses.
Solution Approach 2:
The system performs preliminary detection of ventricular mechanical activity before delivering pacing stimuli. By using the accelerometer to detect upcoming ventricular contractions in advance, the system can pre-plan pacing timing to ensure synchronous delivery, preventing arrhythmia triggering while maintaining appropriate ventricular support.
3Measurement precision
If mechanical activity sensing is added to detect ventricular contractions, then reliable detection during therapy is achieved, but device complexity increases
Solution Approach 1:
The patent merges the accelerometer sensor with the existing pacemaker/defibrillator device architecture. The mechanical activity sensing capability is integrated into the existing telemetry and processing systems, combining multiple functions (electrical sensing, mechanical sensing, pacing, defibrillation) into a unified device platform, thereby reducing overall system complexity despite adding new sensing modality.
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
Enables reliable detection of ventricular activity and controlled pacing, minimizing the risk of triggering ventricular arrhythmias by using mechanical activity signals to ensure synchronized ventricular stimulation during antitachycardia atrial pacing therapy.
Implementation Method 1
a sensor responsive to mechanical activity of the myocardium, able to deliver a mechanical activity signal representative of the mechanical movements produced by the contractions of the ventricular cavity
Data Source
AI summary
An implantable medical device includes a mechanical activity sensor configured to sense movements produced by contractions of a ventricular cavity and output a mechanical activity signal representative of the contractions. The implantable medical device also includes one or more circuits configured to detect a plurality of spontaneous ventricular depolarizations based on electrical potentials representative of the spontaneous ventricular depolarizations, calculate an escape interval, and provide an antibradycardia ventricular pacing therapy in an absence of a detected spontaneous ventricular event after the escape interval. The circuits calculate the escape interval by calculating a first escape interval based on successive detected spontaneous ventricular depolarizations and a second escape interval based on the mechanical activity signal from the mechanical activity sensor, and selecting one of the first escape interval and the second escape interval, wherein the second escape interval is selected in response to a delivery of an antitachycardia atrial pacing therapy.