Electro-mechanical disorders in cardiac function result in arrhythmias. Due to the non-stationary
nature of these arrhythmias and, owing to lethality associated with certain type of arrhythmias,
they are challenging to study. Most of the existing studies are limited in that they extract electrical
activity from surface intracardiac electrical activity, either through the use of electrical or optical
mapping. One way of studying current pathways inside and through biological tissues is by using
Magnetic Resonance Imaging (MRI) based Low Frequency Current Density Imaging (LFCDI).
For the first time CDI was used to study ex-vivo beating hearts in different cardiac states. It
should be said that; this approach involves heavy logistical and procedural complexity, hence, it
would be beneficial to adapt existing electrophysiological computer models to investigate and simulate current density maps specific to studying cardiac function. In achieving this, the proposed
work presents an approach to model the current density maps in 3D and study the current distributions
in different electrophysiological states of the heart. The structural and fiber orientation of
the heart used in this study were extracted using MRI-based Diffusion Tensor Imaging. The monodomain
and bidomain Aliev-Panfilov electrophysiological models were used for CDI modeling,
and the results indicate that different states were distinguishable using range and correlation of
simulated current density maps.
The obtained results through modeling were corroborated with actual experimental CDI data
from porcine hearts. Individually and comparatively, the experimental and simulation results for
various states have the same trend in terms of variations (trend correlation coefficients ≥ 0.98) and
state correlations (trend correlation coefficients ≥ 0.89). The results also show that the root mean
square (RMS) error in average range ratios between bidomain CDI model results and real CDI data
is 0.1972 and the RMS error in state correlations between bidomain CDI model results and real
CDI data is 0.2833. These results indicate, as expected, the proposed bidomain model simulation
of CDI corroborates well with experimental data and can serve as a valuable tool for studying
lethal cardiac arrhythmias under different simulation conditions that are otherwise not possible or
difficult in a real-world experimental setup.
Simulation models of current density imaging in studying cardiac states
