Cardiac Function Determination via Pre-Ejection Period Correction
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Solution Overview
Problem
Conventional methods for determining pulse wave velocity fail to accurately account for the pre-ejection period, leading to significant errors in pulse wave velocity measurements, which are crucial for assessing cardiovascular health.
Innovation Solution
A method that determines pre-ejection period and pulse wave velocity by measuring anatomical characteristics such as pulse delays and arterial tree distances, allowing for accurate calculation of pulse wave velocity and cardiac output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods (Frank method or PWV original method) are used to determine pulse wave velocity, then the measurement process is simplified, but the measurement precision deteriorates due to failure to account for pre-ejection period
Solution Approach 1:
The patent segments the pulse wave velocity measurement into two distinct components: pre-ejection period (PEP) and pulse transit time (PTT). By measuring PEP separately using an electrocardiogram sensor to detect the QRS complex onset and aortic valve opening, and PTT separately using pulse wave sensors, the total pulse delay can be accurately decomposed. This segmentation allows each component to be measured and calculated independently, improving overall measurement precision while maintaining manageable complexity through modular measurement steps.
Solution Approach 2:
The patent applies preliminary action by measuring and calculating the pre-ejection period before determining the pulse transit time. The QRS complex onset is detected first, followed by aortic valve opening detection, establishing the PEP baseline. This preliminary measurement of PEP is then subtracted from the total pulse delay to isolate the true PTT, ensuring that the pre-ejection period does not contaminate the pulse wave velocity calculation. This sequential approach prevents error propagation.
2Reliability
If conventional methods are used, then ease of operation is improved, but reliability deteriorates due to significant errors in pulse wave velocity determination
Solution Approach 1:
The patent merges multiple measurement modalities into a unified cardiovascular assessment system. Electrocardiogram sensors are combined with pulse wave sensors at different body sites (carotid and femoral arteries) to simultaneously capture electrical cardiac activity and mechanical pulse wave propagation. This merging allows the system to compute both pre-ejection period from ECG and pulse transit time from pulse waves, then integrate these measurements to derive accurate pulse wave velocity and cardiovascular characteristics, significantly improving reliability through multi-parameter validation.
Solution Approach 2:
The patent introduces the pre-ejection period as an intermediary variable that mediates between the QRS complex onset and the pulse wave arrival time. By using PEP as an intermediate measurement step, the system can isolate the true pulse transit time component from the total pulse delay. This intermediary PEP measurement acts as a correction factor that eliminates the systematic error present in conventional methods, thereby improving the reliability of pulse wave velocity determination without substantially complicating the measurement procedure.
Data Source
AI summary
A method for determining a cardiac function, comprising (i) determining base anatomical characteristics associated with the subject, (ii) determining pulse delay to a first body site (PD01) and a second body site (PD02) as a function of the anatomical characteristics, wherein the distance via the arterial tree from the aortic valve to the first body site (PD01) is different than the arterial tree distance from the aortic valve to the second body site (PD02), (iii) determining pulse wave velocity between the first body site and the second body site (PWV12), (iv) determining pulse wave velocity between the aortic valve and the first body site (PWV01) as a function of PWV12, and the anatomical characteristics; and (v) determining the pre-ejection period (PEP) as a function of PD01 and PWV01.