Planning of surgical antiarrhythmic interventions based on simulations of cardiac electrophysiology

Objectives: Surgical ablation procedures in atrial fibrillation originate from experiences made with the Cox-/Maze-procedure. Aiming at a better adaptation of the extent of surgery in individuals, a computer model based planning environment for this rhythm disorder was developed and validated using a Langendorff preparation of domestic pig hearts (n=8).

Material and Methods: Mathematical models are used to describe the electrophysiology of each single cell with a rule based system depending on tissue type, stimulus frequency and refractory period. Another model couples cells to a multi-cellular-environment including tissue heterogeneities, fiber orientation and specific properties of the cardiac conduction system. Simulation results were validated in a porcine Langendorff preparation. Performing a spiral CT scan, a balloon catheter (EnSite-System) for endocardial mapping was sequentially introduced into all four heart chambers to record the electrical excitation propagation in the beating heart.

Results: The data acquired in the experiments corresponded exactly to the calculated potentials based on the computer simulations. The model offered a near real time time-resolution in sinus rhythm and atrial fibrillation. The morphological and electrophysiological properties were adequately presented allowing exact planning and performing of ablation lines to terminate atrial fibrillation.

Conclusions: For the first time, this model of combined cardiac electrophysiologic and morphological properties allows simulation of the effects of ablation lines to terminate atrial fibrillation. The study provides a new tool to improve the quality of surgical ablation procedures.