Cardiac Stimulation Device AV Node Activation Time Optimization
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Solution Overview
Problem
Current methods for optimizing ventricular-ventricular (VV) delays in cardiac resynchronization therapy (CRT) are limited by the need for invasive procedures and inability to continuously optimize settings outside a clinical setting, as well as inefficiencies in managing changing optimal VV-delays due to disease progression.
Innovation Solution
An implantable cardiac stimulation device system and method that estimates the time for depolarization waves to reach the AV node in both ventricles, allowing for dynamic adjustment of pacing therapy based on activation time intervals, using electrodes positioned near the HIS bundle or coronary sinus to detect retrograde conduction and calculate optimal VV-delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If echocardiography or invasive LV dP/dt measurements are used to select optimal VV-delay, then measurement precision is improved, but device complexity and inability to continuously optimize outside clinic worsens
Solution Approach 1:
The device automatically measures intracardiac electrograms and calculates optimal VV-delay without external intervention. The system performs self-optimization by detecting electrical signals from ventricular depolarization and retrograde conduction through the AV node, eliminating the need for manual echocardiography or invasive measurements while enabling continuous adjustment outside the clinic.
Solution Approach 2:
The patent replaces mechanical/evasive measurement methods (echocardiography, invasive pressure measurements) with electrical signal detection and computational algorithms. By measuring intracardiac electrograms and calculating conduction times through the AV node, the system substitutes physical measurement procedures with electrical signal processing to determine optimal pacing intervals.
2Reliability
If VV-delay is optimized continuously to account for disease progression, then reliability is improved, but ease of operation worsens
Solution Approach 1:
The device continuously monitors intracardiac electrograms and automatically adjusts VV-delay based on measured conduction times. This closed-loop feedback system detects changes in ventricular depolarization and retrograde conduction patterns, dynamically optimizing pacing parameters to accommodate disease progression without requiring manual re-evaluation or external intervention.
Solution Approach 2:
The system performs self-optimization by automatically measuring electrical signals, calculating optimal VV-delay, and adjusting pacing parameters without external intervention. This eliminates the operational burden of continuous manual optimization while maintaining adaptability to changing cardiac conditions over time.
3Ease of operation
If IEGM based optimization methods like QuickOpt are used, then ease of operation is improved, but measurement precision may be compromised
Solution Approach 1:
The patent uses the AV node as an intermediary landmark to measure conduction times. By detecting the time difference between ventricular depolarization and retrograde conduction through the AV node, the system creates a reliable intermediary measurement that bridges the simplicity of IEGM-based methods with the precision needed for accurate VV-delay optimization.
Solution Approach 2:
The system replaces complex multi-parameter measurement approaches with a simplified electrical signal-based method. By measuring intracardiac electrograms and calculating conduction times through the AV node, the patent substitutes complex mechanical/evasive measurements with straightforward electrical signal detection and computation, maintaining both speed and precision.
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
Enables continuous and automatic optimization of VV-delays, improving cardiac function and accelerating reverse remodeling by ensuring synchronized pacing therapy, even in the presence of atrial fibrillation, through precise calculation of activation time intervals.
Implementation Method 1
activating a first ventricle by delivering stimulation to at least one stimulation site... estimating a point of time for arrival at the AV node for at least one depolarization wave resulting from the stimulation
Implementation Method 2
using electrodes positioned near the HIS bundle or coronary sinus to detect retrograde conduction and calculate optimal VV-delays
Data Source
AI summary
A first ventricle is stimulated at a stimulation site, a point of time for arrival at the AV node for at least one depolarization wave resulting from the stimulation is estimated and a first activation time interval substantially corresponding to the time interval required for at least one depolarization wave to travel from the stimulation site in the first ventricle to the AV node is computed. A similar process is used to compute a second activation time interval for the other ventricle. Based on these activation time intervals and a difference between the intervals, a pacing therapy can be determined.