[New functions and variables to characterize and compare vectorcardiograms (author's transl)]

Area of Science:

• Cardiology
• Biomedical Engineering
• Signal Processing

Context:

• Current electrographic data exhibit high variability, complicating the differentiation between normal and abnormal cardiac electrical activity.
• Measurement errors, particularly in identifying QRS complex timing and accounting for cardiac displacement, contribute significantly to data variability and reduced comparability.
• Existing methods struggle to reliably distinguish subtle physiological changes from noise, impacting diagnostic precision.

Purpose:

• To introduce a novel system for describing cardiac electrical activity using invariant vector loop functions (v, w, u).
• To overcome limitations of traditional electrocardiography (ECG) and vectorcardiography (VCG) by minimizing variability caused by measurement errors and positional changes.
• To enhance the interpretability of electrographic data for physiological processes and improve diagnostic capabilities.

Summary:

• Three new time-dependent functions (v, w, u) are proposed to characterize the cardiac vector loop, invariant to spatial positioning.
• Function 'v' represents the rate of change in the magnitude of the resultant electrical vector.
• 'w' measures the projection of the derivative vector onto an orthogonal plane, indicating the peak's velocity along the loop.
• 'u' quantifies the deviation from a planar trajectory, offering an 'edgeside' view of the loop.
• These functions, combined with traditional vectorial data, form a comprehensive descriptive system.

Impact:

• The proposed vectorial description system significantly reduces external influences, such as thoracic shape, on ECG and VCG data.
• This approach allows for a more accurate interpretation of cardiac electrical activity, directly reflecting underlying physiological processes.
• The method is particularly advantageous for preventive testing, enabling more reliable discrimination between normal and abnormal cardiac conditions.