Capture Threshold Measurement for Pacing Vector Selection
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Solution Overview
Problem
Current methods for determining heart tissue pacing capture thresholds in implantable medical devices are time-consuming and inefficient, as they require testing multiple vectors to find the optimal energy level for pacing without depleting the device's battery unnecessarily.
Innovation Solution
The technique involves measuring the time interval between a pacing stimulus delivered to one ventricle and the subsequent depolarization of another ventricle to determine capture, allowing for iterative adjustment of pacing pulse magnitude to quickly and accurately estimate capture thresholds for various pacing vector configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods are used to determine pacing capture thresholds by testing multiple vectors with incrementally increasing or decreasing magnitudes, then capture threshold determination is achieved, but the process is time-consuming and inefficient
Solution Approach 1:
The patent applies preliminary action by first establishing a capture window based on a preliminary capture threshold determination, then using this window to efficiently test multiple vectors. The capture window is predetermined based on initial testing, allowing subsequent vector threshold determinations to be performed more rapidly within this established timeframe, thus reducing overall testing time while maintaining accuracy.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying pacing vector parameters (electrode combinations, pulse magnitudes, pulse widths) while maintaining a fixed capture window duration. This allows rapid comparison of different vectors against the same temporal reference, enabling efficient threshold determination across multiple vectors without repeatedly adjusting the detection parameters.
2Adaptability or versatility
If multiple pacing vectors are tested to find optimal energy levels, then efficient pacing selection is achieved, but battery energy is consumed during the testing process
Solution Approach 1:
The patent applies partial action by testing pacing vectors at a limited set of discrete magnitude levels rather than exhaustively testing all possible magnitudes. The capture window is established at a sufficient but not excessive duration, providing adequate detection capability while minimizing the energy required for each test pulse and the total number of tests needed.
Solution Approach 2:
The patent implements feedback by using the capture window detection results to guide subsequent vector testing. When capture is detected within the window, the system provides feedback that confirms adequate pacing threshold, allowing the testing process to terminate or adjust accordingly, thus avoiding unnecessary additional energy consumption from exhaustive testing of all vectors.
Data Source
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AI summary
Various techniques for facilitating selection of a pacing vector for pacing a chamber of a heart are described. A medical deviceis configured, for each of a plurality of vectors, to deliver a pacing pulse to capture a first heart chamber, to determine a first time interval between the pacing pulse and a sensed event in a second heart chamber, to determine a capture detection window in response to the determined first time interval, and to enable a capture detection module to iteratively decrease a pacing pulse magnitude delivered in the first heart chamber until an event in the second heart chamber is not sensed during the determined capture detection window.