Dynamic electrocardiography. III. The "imaginary cardiac vector" hypothesis: theoretical basis

Area of Science:

• Cardiovascular physiology
• Biophysics
• Medical instrumentation

Background:

• The cardiac vector is conventionally represented as a real vector in electrocardiography and vectorcardiography.
• This representation is based on treating scalar electrocardiogram (ECG) voltages as vector components.
• The historical origin of the cardiac vector is often attributed to Einthoven in 1913.

Purpose of the Study:

• To critically evaluate the "imaginary cardiac vector" hypothesis.
• To determine if the cardiac vector is a "real" vector entity or a misinterpretation of scalar quantities.
• To re-examine Einthoven's original methods and findings regarding the cardiac vector.

Main Methods:

• Analysis of the "imaginary cardiac vector" hypothesis.
• Review of Einthoven's original 1913 methods and data.
• Comparison of classical ECG/vectorcardiography techniques with fundamental principles of vector mathematics.

Main Results:

• The study demonstrates that the theoretical foundation of the cardiac vector is fundamentally flawed.
• Voltage, the basis of ECG measurements, is a scalar, not a vector quantity.
• Einthoven's original procedures were scalar, not vector-based, and he did not describe a vector.

Conclusions:

• The "cardiac vector" as commonly understood and taught is an "imaginary" construct, not a real vector.
• Classical electrocardiographic analysis misinterprets scalar voltage data as vector components.
• The historical basis for the cardiac vector in electrocardiography requires re-evaluation.