Summary
Objectives:
In this paper, we present a unified electrodynamic heart model that permits simulations
of the body surface potentials generated by the heart in motion. The inclusion of
motion in the heart model significantly improves the accuracy of the simulated body
surface potentials and therefore also the 12-lead ECG.
Methods:
The key step is to construct an electromechanical heart model. The cardiac excitation
propagation is simulated by an electrical heart model, and the resulting cardiac active
forces are used to calculate the ventricular wall motion based on a mechanical model.
The source-field point relative position changes during heart systole and diastole.
These can be obtained, and then used to calculate body surface ECG based on the electrical
heart-torso model.
Results:
An electromechanical biventricular heart model is constructed and a standard 12-lead
ECG is simulated. Compared with a simulated ECG based on the static electrical heart
model, the simulated ECG based on the dynamic heart model is more accordant with a
clinically recorded ECG, especially for the ST segment and T wave of a V1-V6 lead
ECG. For slight-degree myocardial ischemia ECG simulation, the ST segment and T wave
changes can be observed from the simulated ECG based on a dynamic heart model, while
the ST segment and T wave of simulated ECG based on a static heart model is almost
unchanged when compared with a normal ECG.
Conclusions:
This study confirms the importance of the mechanical factor in the ECG simulation.
The dynamic heart model could provide more accurate ECG simulation, especially for
myocardial ischemia or infarction simulation, since the main ECG changes occur at
the ST segment and T wave, which correspond with cardiac systole and diastole phases.
Keywords
Electromechanical heart model - finite element method - electrocardiogram - myocardial
ischemia