Cardiac Activation Cycle Length Detection from Segmented Electrograms
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Solution Overview
Problem
Current methods for determining cardiac activation cycle length during atrial fibrillation are inadequate due to the variability of cardiac signals and the unsuitability for use with a mapping catheter, leading to inaccurate and unreliable LCL measurements.
Innovation Solution
A device and method for determining cardiac activation cycle length that includes preprocessing electrogram data to remove noise, detecting non-overlapping activation segments, and determining periodicity by comparing interval durations, with optional post-processing to refine segment detection and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional signal processing methods (FFT, autocorrelation) are used to determine cycle length, then the measurement process is simple, but the accuracy and reliability of LCL measurements deteriorate due to signal variability and noise
Solution Approach 1:
The patent segments the electrogram signal into distinct activation segments by detecting local extrema (peaks and troughs) and grouping them into non-overlapping segments. This segmentation allows the system to isolate and analyze specific activation events rather than processing the entire complex signal at once, thereby improving measurement precision while maintaining manageable complexity
Solution Approach 2:
The patent extracts and removes noise components from the electrogram signal through preprocessing steps before cycle length determination. By separating the useful activation signals from the harmful noise and baseline wander, the system achieves more accurate LCL measurements without significantly increasing the overall complexity of the measurement process
2Measurement precision
If adaptive thresholding methods based on amplitude detection are used, then the method is more sophisticated and potentially more accurate, but the device complexity and processing requirements increase
Solution Approach 1:
The patent applies local quality analysis by examining the characteristics of each activation segment individually through detection of local extrema. Instead of using a single global threshold for the entire signal, the system adapts to local signal properties at each activation event, improving measurement precision while keeping the processing approach relatively simple and systematic
Solution Approach 2:
The patent performs preliminary preprocessing actions on the electrogram signal before the main cycle length determination. By pre-processing to remove noise and baseline wander in advance, the system simplifies the subsequent activation detection and cycle length calculation, reducing the overall processing complexity while maintaining high accuracy
3Ease of operation
If the mapping catheter moves during ablation procedures, then the clinician can perform ablation operations, but the signal quality deteriorates due to added noise and far-field activity
Solution Approach 1:
The patent converts the harmful effect of catheter movement and associated noise into a beneficial outcome by using the movement information to trigger and delimit activation segments. The system identifies activations based on local extrema that occur during catheter movement phases, effectively using the disturbance to highlight genuine activation events while filtering out spurious signals
Solution Approach 2:
The patent employs dynamic analysis by continuously monitoring the electrogram signal and adapting the activation detection criteria based on real-time signal characteristics. The system dynamically identifies activation segments as they occur during catheter movement, maintaining reliable measurements despite changing operational conditions without requiring the catheter to remain stationary
Data Source
AI summary
A device for determining a cardiac activation cycle length including a memory arranged so as to store electrogram data having time stamps and associated with a channel. The device includes a preparer arranged so as to receive electrogram data associated with a given channel and with a time window of at least 1.5 seconds. The device includes a detector arranged so as to receive the pre-processed data and to detect therein non-overlapping activation segments that each correspond to a window within said time window of at least 1.5 seconds. The device includes a computer arranged so as to determine a periodicity condition of the activations by determining in each activation segment a reference time point and by comparing the duration of intervals each defined by two reference time points consecutive to the duration of the time window of at least 1.5 seconds.