Sequential change in the different of potential distribution between a normal subject and simulated torso model

Area of Science:

• Cardiology
• Biophysics
• Medical Imaging

Background:

• Electrocardiography (ECG) is crucial for understanding cardiac electrical activity.
• Mathematical models, like the dipole model, attempt to simulate ECG signals.
• Accurate simulation of ventricular activation spread is essential for diagnosing heart conditions.

Purpose of the Study:

• To compare measured isopotential maps from ECGs with simulated maps based on a dipole model.
• To identify discrepancies in potential distribution during ventricular activation.
• To assess the utility of difference maps in understanding ventricular activation spread.

Main Methods:

• Acquired 85 unipolar lead ECGs from a normal subject.
• Generated measured isopotential maps every 3 msec.
• Created simulated maps using a single, fixed cardiac dipole model.
• Quantitatively compared measured and simulated maps, generating difference maps.

Main Results:

• Good agreement between measured and simulated maps was observed during early ventricular activation.
• Significant differences in potential distribution emerged around epicardial breakthrough.
• The dipole model became insufficient to represent cardiac electromotive force post-breakthrough.

Conclusions:

• The single dipole model accurately represents early ventricular activation but fails post-epicardial breakthrough.
• Difference maps effectively highlight deviations from the dipole model.
• Difference maps around epicardial breakthrough show promise for estimating ventricular activation spread.