Multi-site Pacing Vector Recharge Control
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Solution Overview
Problem
Current cardiac resynchronization therapy (CRT) systems are limited by predetermined recharge time periods and lack flexibility in pacing and recharge configurations, which can lead to suboptimal resynchronization therapy and increased side effects such as phrenic nerve stimulation.
Innovation Solution
The implementation of a method and circuitry that allows for adjustable coupling capacitor recharge times based on voltage sensed at the pacing site, enabling multiple pacing vectors with independent energy characteristics and recharge times, and prioritizing recharge completion to prevent electrode corrosion and optimize therapy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If predetermined recharge time periods are used in CRT systems, then the system operation is simplified, but the therapy optimization is limited and side effects increase
Solution Approach 1:
The patent implements dynamic recharge time adjustment by measuring the actual voltage across the coupling capacitor and comparing it to threshold values. The recharge period is extended or shortened based on the measured voltage level, allowing the system to adapt to varying tissue conditions and pacing requirements while maintaining automated operation.
Solution Approach 2:
The system incorporates feedback mechanisms by continuously monitoring the voltage across the coupling capacitor during the recharge period. This voltage information is fed back to the control logic, which adjusts the recharge timing accordingly, enabling optimized therapy delivery without requiring manual intervention.
2Adaptability or versatility
If multiple pacing vectors with different energy characteristics are implemented, then therapy effectiveness is improved, but device complexity increases
Solution Approach 1:
The patent segments the pacing function into multiple independent pacing vectors, each with its own output capacitor and coupling capacitor. This allows different energy characteristics to be delivered to different tissue sites while using a modular architecture that manages complexity through systematic division of functions.
Solution Approach 2:
The patent implements a universal control architecture that manages multiple pacing vectors through shared control logic and switching mechanisms. The same basic circuit blocks and control algorithms are reused across different pacing configurations, reducing overall complexity despite the versatility provided by multiple vectors.
3Measurement precision
If coupling capacitor recharge time is extended to absorb residual polarization signal, then sensing accuracy is improved, but pacing efficiency decreases
Solution Approach 1:
The system uses feedback control by measuring the actual voltage across the coupling capacitor and adjusting the recharge period duration based on the measured value. This allows the recharge time to be extended only as much as necessary to achieve adequate signal absorption, avoiding unnecessary delays in pacing delivery.
Solution Approach 2:
The patent dynamically changes the recharge time parameter based on the measured voltage conditions. When the voltage indicates sufficient charge absorption, the recharge period is terminated early, maintaining pacing efficiency. When higher charges are present, the recharge period is extended appropriately, ensuring sensing accuracy.
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
This approach enhances the flexibility and efficiency of CRT by optimizing pacing and recharge configurations, reducing side effects, and improving cardiac resynchronization therapy outcomes.
Implementation Method 1
The recharging path includes the tissue-electrode interface and a coupling capacitor that can absorb residual post-pace polarization signal
Implementation Method 2
One purpose of a recharge operation is to address net charges that occur due to redox reactions which generate gases (e.g. H2, O2, Cl2) at the electrode interface
Data Source
AI summary
An implantable device and associated method for delivering multi-site pacing therapy is disclosed. The device comprises a set of electrodes including a first ventricular electrode and a second ventricular electrode, spatially separated from one another and all coupled to an implantable pulse generator. The device comprises a processor configured for selecting a first cathode and a first anode from the set of electrodes to form a first pacing vector at a first pacing site along a heart chamber and selecting a second cathode and a second anode from the set of electrodes to form a second pacing vector at a second pacing site along the same heart chamber. The pulse generator is configured to deliver first pacing pulses to the first pacing vector and delivering second pacing pulses to the second pacing vector. The pulse generator generates a recharging current for recharging a first coupling capacitor over a first recharge time period in response to the first pacing pulses. The pulse generator for generating a recharging current for recharging a second coupling capacitor over a second recharge time period in response to the second pacing pulses. An order of recharging the first and second coupling capacitors is dependent upon one of ventricular pacing mode, left ventricle to right ventricle delay (V-V) pace delay, multiple point LV delay and latest delivered pacing pulses to one of the first and second pacing vectors.