Selective Heart Pacing Using AV Delay Sub-Space Analysis
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Solution Overview
Problem
Existing implantable medical devices face challenges in identifying suitable periods for listening to intrinsic atrioventricular (AV) propagation, leading to potential AV block or long AV delays, which can cause non-physiologic PR intervals, pacemaker-mediated tachycardia, and artificially limited maximum tracking rates.
Innovation Solution
An implantable medical device with a signal processor, delay measurer, sensor arrangement, and sub-space processor that measures AV delays and physiological parameters to generate decision support information, allowing for selective pacing algorithms to determine optimal timing for ventricular pacing based on the probability of AV conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the device withholds atrium triggered pacing to monitor intrinsic AV conduction, then ventricular pacing is minimized, but long AV delays occur causing non-physiologic PR intervals and pacemaker-mediated tachycardia
Solution Approach 1:
The device performs preliminary assessment of intrinsic AV conduction capability before withholding pacing. By evaluating conduction status in advance, the system determines whether it is safe to withhold atrium-triggered pacing, thereby avoiding long AV delays while still minimizing unnecessary ventricular pacing.
Solution Approach 2:
The device continuously monitors AV conduction and uses this feedback to dynamically adjust pacing decisions. When intrinsic conduction is detected, the system withholds pacing; when conduction is absent or delayed, the system resumes pacing to prevent long AV delays and associated complications.
2Reliability
If the device continuously monitors for intrinsic conduction, then ventricular pacing is reduced, but the heart performs in a non-optimal way during listening periods
Solution Approach 1:
The device performs preliminary assessment of intrinsic AV conduction capability before withholding pacing. By evaluating conduction status in advance, the system determines whether it is safe to withhold atrium-triggered pacing, thereby avoiding long AV delays while still minimizing unnecessary ventricular pacing.
Solution Approach 2:
Instead of continuous monitoring, the device uses periodic assessment of intrinsic AV conduction at strategically timed intervals. This approach reduces the duration of suboptimal heart performance while still effectively identifying suitable periods for pacing withdrawal, balancing conduction detection with maintained heart function efficiency.
3Reliability
If the device implements selective pacing algorithms, then ventricular pacing is minimized, but the complexity of the device increases
Solution Approach 1:
The complex algorithmic functions are extracted from the implantable device and implemented in an external programmer or processing system. The implantable device retains only essential sensing and basic pacing functions, while the sophisticated selective pacing logic resides externally, reducing device complexity while maintaining high selective pacing accuracy.
Solution Approach 2:
An intermediary processing layer is introduced between the simple device sensors and the complex pacing decisions. This intermediary (external programmer or separate processing unit) handles the complex algorithmic computations, allowing the implantable device itself to remain relatively simple while still achieving accurate selective pacing through coordinated operation with the intermediary system.
Data Source
AI summary
An implantable medical device measures an AV delay in connection with measurement of N physiological patient parameters. The parameters are used for identifying a sub-space of an N-dimensional parameter space. An expected AV delay is assigned to the identified sub-space based on the measured AV delay, where the parameter space with expected AV delays constitute decision support information to be used by the device for performing a selective heart pacing. This selective pacing is performed based on a priori probability determined using the support information and a measured set of N parameters. The a priori probability represents the probability of successful AV conduction at a current patient condition determined based on the measured parameters.