T-wave morphology detection for ventricular dyssynchrony in implantable devices
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Solution Overview
Problem
Conventional methods for detecting ventricular dyssynchrony in heart failure patients, particularly those undergoing cardiac resynchronization therapy (CRT), rely on QRS-complex-based techniques that are suboptimal when ventricles are paced by an implanted device, as they cannot accurately detect dyssynchrony during therapy delivery due to changes in QRS-complex morphology and timing.
Innovation Solution
The use of T-wave-based detection methods in implantable medical devices, which measure morphological features such as peak number, area, inflection points, and slope of the T-wave to assess ventricular dyssynchrony, allowing for continuous monitoring and adjustment of pacing parameters to reduce dyssynchrony without requiring natural ventricular beats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If QRS-complex-based techniques are used to detect ventricular dyssynchrony, then detection can be performed during natural heartbeats, but the detection accuracy deteriorates when ventricles are paced by an implanted device due to changes in QRS-complex morphology and timing
Solution Approach 1:
The patent changes the detection parameter from QRS-complex morphology to T-wave morphology. Specifically, it uses T-wave amplitude, duration, and shape characteristics which remain reliable during paced beats, whereas QRS-complex parameters become unreliable due to pacing-induced morphological changes. This parameter substitution resolves the contradiction by maintaining detection accuracy across both natural and paced heartbeats.
2Ease of manufacture
If conventional QRS-complex-based detection is used, then the method is simple to implement, but it cannot accurately detect dyssynchrony during CRT therapy delivery
Solution Approach 1:
The invention substitutes T-wave parameters for QRS-complex parameters in the detection algorithm. T-wave morphology (amplitude, duration, shape) provides reliable dyssynchrony information during paced beats without complicating the implementation. The method maintains algorithmic simplicity while achieving accurate detection during CRT therapy by relying on the stability of T-wave characteristics under pacing conditions.
3Productivity
If continuous monitoring of ventricular dyssynchrony is implemented during CRT, then real-time adjustment of pacing parameters is enabled, but the complexity of the device increases
Solution Approach 1:
The patent employs T-wave parameters (amplitude, duration, morphology) that can be extracted and analyzed using relatively simple signal processing algorithms. This approach enables continuous real-time monitoring during CRT therapy without requiring complex computational resources or additional hardware, thus achieving real-time dyssynchrony assessment while minimizing increases in device complexity.
Data Source
AI summary
Techniques are provided for detecting and evaluating ventricular dyssynchrony based on morphological features of the T-wave and for controlling therapy in response thereto. For example, the number of peaks in the T-wave, the area under the peaks, the number of points of inflection, and the slope of the T-wave can be used to detect ventricular dyssynchrony and evaluate its severity. As ventricular dyssynchrony often arises due to heart failure, the degree of dyssynchrony may also be used as a proxy for tracking the progression of heart failure. Pacing therapy is automatically and adaptively adjusted based on the degree of ventricular dyssynchrony so as to reduce the dyssynchrony and thereby improve cardiac function.