Biosystems Engineering Laboratory

Atrial simulation

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Atrial fibrillation

Why AF is LA disease?

  • Fibrillation wavelet is also conducted in the right atrium.
  • Normally, action potential duration (APD) of the conventional LA is smaller than the APD of the right atrium.
  • AF driver is mostly in the left atrium
  • On clinical judgment, AF is commonly known as left atrium disease

The relationship between AF and stroke

  • Atrial fibrillation is the cause of cerebral infarction
  • Patients with AF have five times higher rate of stroke compared to the general population, a stroke occurs among 15~20% of AF patients
  • The objective of this study is to establish the guiding of an appropriate location for effective surgery of AF

Theoretical background & geometry

NavX data

  • NavX datas are results measured directly during clinical surgery.
  • NavX data contain CT data, and this one also contains Pulmonary vein, scar zone, catheter’s information used in surgical procedures

Complex fractioned atrial electrogram(CFAE)

  • CFAE is calculated from electrical signals through 2 electrodes connected to the catheter
  • Setting electrode on atrial tissue → the EGM difference from two electrodes is BIPOLAR EGM → analysis of EGM results → the messy part of the frequency is called CFAE

CT data

  • In order to conduct FEM analysis of left atrial, we used the shape modeler program for segmentation of NavX data, after that, we proceeded to the smoothing. Then we developed S/W software to increase the number of mesh.

Electrophysiology of atrial cell

  • CRN model was used in this study.

Verification of atrial cell

  • CRN model was basically created from experimental data; and because the compared values and experimental data are presented in the paper, CRN model was numerically equalized.

Verification of atrial cell

  • Because the cell model was identically made from clinical data, and referring to the paper, the following ion channels were modified.
  • After modification of ion channels, the membrane potential was similar to the result of the clinical paper.

Wave propagation model of electric potential

Ablation catheter

  • The effectiveness of the catheter’s front part is to ablate cardiac tissue by using high-frequency.
  • Electrodes on the side of the surface play a role in measuring the eletrogram on both electrodes.

Simulation area

Unipolar EGM

Bipolar EGM

Filter for bipolar EGM

  • In this study, we used 30Hz for low frequency and 500Hz for high frequency

Analysis of CFAE

Voltage map of AF

Simulation result

Conclusion