Dynamic AV Delay Adjustment for Implantable Cardiac Devices
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Solution Overview
Problem
Conventional methods for adjusting atrioventricular delays in implantable medical devices do not account for patient-specific changes in cardiovascular status, leading to potential misalignment in ventricular pacing timing, which can result in suboptimal therapy and loss of AV synchrony.
Innovation Solution
A method and system for dynamically adjusting AV delays based on real-time measurements of AV intervals and heart rate, using a scale factor calculated from base intervals to adapt AV delays and ensure proper timing of ventricular pacing events, regardless of whether the event is sensed or paced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If static AVD programming is performed in-clinic based on echocardiographic or ECG metrics, then initial AV synchrony is achieved, but the therapy becomes suboptimal when patient cardiovascular status changes over time
Solution Approach 1:
The patent implements dynamic AV delay adjustment by continuously measuring AV intervals and automatically modifying AVD and AVDp parameters based on real-time physiological changes. The system transitions from static in-clinic programming to ongoing adaptive adjustment, ensuring AV synchrony is maintained as patient cardiovascular status evolves throughout the day and over time
Solution Approach 2:
The system employs feedback mechanisms by measuring AV intervals (As-Vs and Ap-Vs) in real-time and using these measurements to automatically adjust AV delays. The measured intervals provide continuous feedback about conduction changes, enabling the device to respond appropriately to physiological variations without requiring repeated clinical visits
2Ease of operation
If the conventional approach indirectly calculates AVDp by extending AVDs with a fixed time period, then both AVDs and AVDp are programmed, but the AVDp may not provide proper AV synchrony when the device switches between atrial sensing and atrial pacing
Solution Approach 1:
The system measures actual Ap-Vs intervals during atrial pacing events and uses these direct measurements to calculate AVDp, rather than relying on indirect calculation from As-Vs intervals. This feedback loop ensures AVDp is accurately tailored to the patient's specific conduction characteristics during paced atrial events, improving ventricular pacing timing accuracy
Solution Approach 2:
The patent dynamically adjusts both AVDs and AVDp parameters based on measured AV intervals. By changing these parameters in response to real-time measurements, the system ensures both sensed and paced AV delays remain optimized for current physiological conditions, resolving the timing inaccuracies that occur with fixed or indirectly calculated values
Data Source
AI summary
A method and device for dynamic device based AV delay adjustment is provided. The method comprises 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 for detecting an atrial paced (Ap) event or atrial sensed (As) event, and measures an AV interval corresponding to an interval between the Ap event or the As event and a sensed ventricular (Vs) event. The AV interval is associated with a current heart rate (HR). The method automatically dynamically adjusts a first AV delay based directly on the measured AV interval, identifies a scale factor associated with the current HR, calculates a second AV delay by scaling the first AV delay based on the scale factor and manages a pacing therapy, utilized by the IMD, based on the first and second AV delays.