Use of a biophysical model of atrial fibrillation in the interpretation of the outcome of surgical ablation procedures.

Objective: To determine the adequacy of 'in silico' biophysical models of atrial fibrillation (AF)in the design of different ablation tine patterns. Background: Permanent AF is a severe medical problem for which (surgical) ablation is a possible treatment. The ideal ablation pattern remains to be defined. Methods: Forty-six consecutive adult patients with symptomatic permanent drug refractory AF underwent mitral surgery combined with non-transmural, (n = 20) and transmural (n = 26) radiofrequency Minimaze. The fraction of 'in vivo' conversions to sinus rhythm (SR) in both groups was compared with the performance of the fraction of 'in silico' conversions observed in a biophysical model of permanent AF The simulations allowed us to study the effectiveness of incomplete and complete ablation patterns. A simulated, complete, transmural Maze III ablation pattern was applied to 118 different episodes of simulated AF set-up in the model and its effectiveness was compared with the clinical results reported by Cox. Results: The fraction of conversions to SR was 92% 'in vivo' and 88% 'in silico' (p = ns) for transmural/complete ablations, 60% respectively 65% for non-transmural/incomplete Minimaze (p = ns) and 98% respectively 100% for Maze III ablations (p = ns). The fraction of conversions to SR 'in silico' correlated with the rates 'in vivo' (r(2) = 0.973). Conclusions: The fraction of conversions to SR observed in the model. closely corresponded to the conversion rate to SR post-surgery. This suggests that the model. provides an additional, non-invasive toot for optimizing ablation tine patterns for treating permanent AF (c) 2007 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.