Dynamic AV Delay Adjustment in Implantable Cardiac Devices
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Solution Overview
Problem
Current implantable medical devices (IMDs) for cardiac resynchronization therapy (CRT) use static atrioventricular (AV) delay settings, which do not account for short-term or long-term changes in a patient's cardiovascular status, leading to suboptimal ventricular depolarization and cardiac output due to inadequate dynamic adjustment of AV timing.
Innovation Solution
The implementation of a method and system that dynamically adjusts AV delay based on percentage-based offsets derived from measured AV intervals, using electrodes located near atrial, right ventricular, and left ventricular sites, allowing for real-time adjustment of pacing therapy to match changing heart rates and conduction conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If static AV delay settings are used in implantable medical devices, then device complexity is reduced and ease of operation is improved, but adaptability to changing cardiovascular status deteriorates and therapeutic effectiveness decreases
Solution Approach 1:
The patent implements dynamic AV delay adjustment by continuously measuring intrinsic AV intervals and automatically adjusting the AV delay parameter based on measured values and pre-programmed algorithms. This transforms the static AV delay setting into a dynamic parameter that adapts to changing heart rates and conduction conditions, resolving the contradiction between adaptability and device complexity
Solution Approach 2:
The system employs feedback mechanisms by measuring the intrinsic AV interval continuously and using this measured information to adjust the AV delay parameter. The device monitors cardiovascular status changes and feeds this information back to the control algorithm, which then modifies the pacing therapy accordingly, enabling adaptability without requiring complex manual reprogramming
2Productivity
If static AV delay settings are used, then ease of operation is improved, but cardiac output and electrical synchrony deteriorate due to inadequate dynamic adjustment
Solution Approach 1:
The patent enables the device to self-adjust the AV delay parameter automatically based on pre-programmed algorithms and real-time measurements of intrinsic AV intervals. The system performs self-optimization of pacing therapy without requiring clinician intervention for each change, improving cardiac output through dynamic adaptation while maintaining ease of operation by eliminating the need for frequent manual adjustments
Solution Approach 2:
The system dynamically changes the AV delay parameter based on measured intrinsic AV intervals and pre-programmed relationships. By automatically adjusting this critical timing parameter in response to changing cardiovascular conditions, the device optimizes ventricular depolarization and cardiac output without burdening the user with complex programming tasks
3Measurement precision
If conventional fixed offset algorithms are used, then device complexity is reduced, but measurement precision and therapeutic effectiveness deteriorate due to inability to account for heart rate dependence
Solution Approach 1:
The patent implements a pre-programmed algorithm that dynamically determines the offset value based on the measured intrinsic AV interval and the relationship between heart rate and AV conduction velocity. Instead of using a fixed offset, the system adjusts the offset parameter according to the measured AV interval, improving measurement precision and therapeutic effectiveness while keeping the algorithm relatively simple through pre-programmed relationships
Data Source
AI summary
A method and device for dynamic device based AV delay adjustment are provided. The method provides electrodes that are configured to be located proximate to an atrial (A) site and a right ventricular (RV) site. The method utilizes one or more processors, in an implantable medical device (IMD), for detecting an atrial paced (Ap) event or atrial sensed (As) event. The method determines a measured AV interval corresponding to an interval between the Ap event or the As event and a ventricular sensed event and calculates a percentage-based (PB) offset based on the measured AV interval. The method automatically dynamically adjusting an AV delay, utilized by the IMD, based on the measured AV interval and the PB offset and manages a pacing therapy, utilized by the IMD, based on the AV delay after the adjusting operation.