Session S53.3

Effect of Heart Motion on the Solutions of Forward and Inverse Electrocardiographic Problem: A Simulation Study

Y Jiang*, D Farina, O Doessel

Karlsruhe Institute of Technology
Karlsruhe, Germany

Solving the forward problem of electrocardiography provides a better understanding of electrical activities in the heart. The inverse problem of electrocardiography enables a direct view of cardiac sources without catheter interventions. Nowadays the forward and inverse computation is mostly performed in a static model, which is usually built from MRI or CT data of the heart in diastolic state. However, neglecting the heart motion introduces a certain amount of modeling error. This can lead to instability in the forward and inverse solutions.
A dynamic heart model is developed in the current project and used to study the contribution of the heart motion to the simulated ECG and the influence of neglecting cardiac dynamics on the inverse reconstructions. By comparing the simulated ECGs in dynamic and static models significant difference up to 50% in amplitude at the middle of the T-wave can be seen. Tikhonov 0-order regularization and GMRES method are applied to solve the inverse problem for epicardial potentials in both dynamic and static models. The reconstructions using Tikhonov 0-order with dynamic heart model are considerably better than those with static heart model and an improvement of 0.1 in correlation coefficient during the T-wave is shown. But there is no significant difference between the reconstructions with and without the consideration of the heart motion when GMRES method is used, because the GMRES method is more stable against modeling errors.
In further work a more accurate dynamic model will be created from a 4D MRI data-set. Then the forward and inverse computation will be performed in this model. Other regularization methods and source models will be tested on the dynamic model. The effect of respiration on the forward and inverse solutions will also be investigated.

(Abstract Control Number: 154)