Left Ventricular Pacing Timing Correction for Cardiac Resynchronization
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Solution Overview
Problem
Conventional cardiac resynchronization therapy (CRT) algorithms fail to accurately synchronize left ventricular pacing with the earliest intrinsic right ventricular activation, leading to suboptimal treatment outcomes due to inconsistent placement of the right ventricular lead, which can result in dyssynchrony and reduced effectiveness of fusion pacing.
Innovation Solution
A method and system that adjust the timing of left ventricular pacing by applying a correction factor to the pre-excitation interval based on the disparity between the atrial event time and the earliest intrinsic right ventricular activation time, ensuring that pacing occurs before the right ventricular sense time, thereby optimizing the synchronization of ventricular contractions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed pre-excitation interval (50-60 ms) is used for LV pacing, then the device complexity is reduced, but the synchronization accuracy with earliest RV activation deteriorates
Solution Approach 1:
The patent changes the pre-excitation interval parameter dynamically based on the measured offset between RV sense time and earliest RV activation. Instead of using a fixed 50-60 ms interval, the system calculates a corrected pre-excitation interval by adding the measured offset to the standard interval, ensuring accurate synchronization with earliest RV activation while maintaining algorithm simplicity.
2Ease of manufacture
If the RV lead is placed in an electrically late area (e.g., RVOT), then the ease of manufacture and implantation is improved, but the timing accuracy of RV sense relative to earliest activation deteriorates
Solution Approach 1:
The patent employs feedback by measuring the actual offset between RV sense time and earliest RV activation during baseline rhythm detection. This measured offset is then used to correct the pre-excitation interval setting, allowing the system to compensate for suboptimal RV lead placement and achieve accurate LV-RV synchronization despite the lead being in an electrically late area.
3Productivity
If LV pacing is delivered based on standard pre-excitation interval, then the productivity of CRT programming is improved, but the therapeutic effectiveness deteriorates due to pacing into QRS complex
Solution Approach 1:
The patent performs preliminary detection of the offset between RV sense time and earliest RV activation during device implantation or initial programming. This preliminary measurement allows the system to pre-calculate the corrected pre-excitation interval before delivering LV pacing therapy, ensuring that pacing occurs at the optimal time (before QRS complex onset) without requiring complex ongoing adjustments.
Data Source
AI summary
A method and system of cardiac pacing is disclosed. A baseline rhythm is determined. The baseline rhythm includes a baseline atrial event and a baseline right ventricular RV event from an implanted cardiac lead or a leadless device, a pre-excitation interval determined from the baseline atrial event and the baseline RV event, and a plurality of activation times determined from a plurality of body-surface electrodes. A determination is made as to whether a time interval measured from an atrial event to a RV event is disparate from another time interval measured from the atrial event to an earliest RV activation time of the plurality of activation times. A correction factor is applied to the pre-excitation interval to obtain a corrected pre-excitation interval in response to determining the RV event is disparate from the earliest RV activation time. The processor is configured to signal the pulse generator to deliver electrical stimuli to a left ventricle (LV) using the corrected pre-excitation interval before RV sensing time.