The determination of the human ventricular gradient from body surface potential map data

Area of Science:

• Electrophysiology
• Cardiovascular Research
• Biophysics

Background:

• The Wilson ventricular gradient is traditionally conceptualized as a scalar and then a vector quantity.
• Previous analyses have simplified cardiac electrical activity to dipolar or vector representations.

Purpose of the Study:

• To analyze the Wilson ventricular gradient using body surface potential maps.
• To investigate the reduction of surface potential patterns to equivalent dipoles or vectors.
• To determine if cardiac electrical entities (QRS, T, QRST areas) can be fully represented by vectors.

Main Methods:

• Analysis of body surface potential maps.
• Reduction of surface potential patterns to equivalent dipoles/vectors.
• Examination of QRS area, T area, and QRST area.
• Assessment of vector addition principles (QRST area = QRS area + T area).

Main Results:

• The three entities (QRS area, T area, QRST area) did not reduce to vectors with a common origin.
• Conventional vector addition (QRST area = QRS area + T area) was found to be applicable.
• Significant extra-dipolar information remained in all three entities after dipole effect removal.

Conclusions:

• Cardiac electrical activity, as represented by QRS, T, and QRST areas, involves more than simple vector summation.
• Body surface potential maps should be viewed as boundaries of complex electrical fields.
• The findings challenge the sole interpretation of these cardiac electrical patterns as simple surface effects of vectors.