His Bundle Pacing With Delayed Impedance Measurement Timing
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Solution Overview
Problem
Existing implantable medical devices struggle to reliably measure impedance at the His bundle of the heart due to physiological delays in cardiac contraction, making conventional methods infeasible for His bundle pacing.
Innovation Solution
The device employs a specific timing scheme for stimulating the His bundle, followed by delayed impedance measurement, with adjustable periods to account for cardiac signal transitions, allowing reliable impedance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If impedance measurement is performed using conventional timing parameters for right ventricular pacing, then the measurement can be completed quickly, but the impedance measurement becomes unreliable due to physiological delays in cardiac contraction at the His bundle
Solution Approach 1:
The device performs preliminary detection of the R wave (electrical signal indicating ventricular depolarization) before initiating the impedance measurement. This preliminary action allows the system to identify the optimal timing point when cardiac contraction has stabilized, ensuring reliable impedance measurement without requiring excessive waiting time. The R wave detection serves as a trigger that coordinates the impedance measurement with the cardiac cycle phase.
Solution Approach 2:
The system uses feedback from the detected R wave to dynamically adjust the timing of the impedance measurement. By monitoring the electrical signal and using it as a reference point, the device can synchronize the impedance measurement with the appropriate phase of the cardiac cycle, thereby resolving the contradiction between measurement reliability and time delay.
2Measurement precision
If the impedance measurement is delayed to account for cardiac contraction timing, then measurement accuracy improves, but the overall device operation complexity increases
Solution Approach 1:
The detection unit is designed to perform multiple functions: it detects both the R wave (electrical signal) and triggers the impedance measurement based on this detection. By making the detection unit multi-functional, the device avoids adding separate complex control mechanisms, thereby improving measurement accuracy while minimizing the increase in overall device complexity.
Solution Approach 2:
The patent combines the electrical signal detection function and the impedance measurement trigger function into a single coordinated process. The R wave detection and impedance measurement timing are merged into one unified control sequence, simplifying the device architecture while achieving accurate timing coordination for reliable impedance measurement.
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 accurate impedance measurement at the His bundle, providing detailed cardiac cycle information and enabling physiologically appropriate cardiac stimulation.
Implementation Method 1
The detection unit is configured to detect an electrical signal at the His bundle of the same heart
Implementation Method 2
The stimulation unit is configured to stimulate the His bundle of a human or animal heart
Implementation Method 3
the impedance is an important measure of the contractility of the treated heart so that it is also desired to measure the impedance
Data Source
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AI summary
The invention relates to an implantable medical device for stimulating a human or animal heart, comprising a housing (2), a processor, a memory unit, a stimulation unit configured to stimulate the His bundle (18) of a human or animal heart (6), and a detection unit configured to detect an electrical signal at the His bundle (18) of the same heart (6). During operation, the following steps are performed: a) stimulating the His bundle (18) of a human or animal heart (6) with a stimulation pulse (17) delivered by the stimulation unit; b) measuring an electric signal at the His bundle (18) of the same heart (6) with the detection unit upon termination of a first period of time (25) starting upon delivering of the stimulation pulse (17), wherein the first period of time (25) lies in a time range of from 35 ms to 500 ms; c) measuring an impedance (Z) of the same heart (6) with the detection unit upon termination of a second period of time (30) starting upon delivering of the stimulation pulse (17), wherein the second period of time (30) is equal to or longer than the first period of time (25) and lies in a time range of from 50 ms to 500 ms.