Reentrant activity in a virtual 3D ventricular slab preparation subject to regional simulated ischemia: Role of the ischemic zone size

Many aspects about generation of reentrant arrhythmias during regionally acute ischemia remain unclear. The goal of the present work is to study the effects of the size of the central ischemic zone (CZ) in a realistic 3D tissue by means of computer simulations.Simulations were run using a modified version of the Luo-Rudy dynamic action potential model (LRd00) and accounting for fiber orientation in the slab preparation. Our results show that, for a non centered ischemic zone of 25 mm in diameter, premature stimuli applied at coupling intervals comprised between 167 ms and 190 ms lead to reentry. Therefore, the width of the vulnerable window (VW) for re-entry yields 24 ms while for 20 mm in diameter, the VW shrank to 19 ms. In addition, for bigger CZ diameter, figure-of-eight reentries are initiated closer to the epicardium. In conclusion, in a 3D regionally ventricular slab, a bigger size of the ischemic zone widens the VW for reentry.