Effect of Ischemia on the Spatial Heterogeneity of Ventricular Repolarization: a Simulation Study

Aim of this study is to assess, using numerical simulations, the effect of different degrees of ischemia on spatial heterogeneity of ventricular repolarization (SHVR), as evaluated by the V-index. Twelve-lead electrocardiograms were simulated using EGCSIM. Different degrees of ischemia were simulated in three regions, i.e., left anterior descending artery (LAD), right coronary artery (RCA) and left circumflex artery (LCX), by varying the size of the ischemic region (35 mm vs 50 mm), the amplitude of action potentials (APs; maximum reduction of 50%), and by shortening the AP durations (maximum reduction of 35%). The time progression of ischemia was simulated on a time window of 8 minutes in which 30 Monte Carlo simulations of 70 beats were generated each minute. V-index significantly increased at $LCA$ and $RCA$ of 11.2 $\pm$ 1.8 ms (+ 35.4%) and $12.6 \pm 1.6ms (>+ 39.7\%)$ with respect to baseline $(p < 0.05)$, for the ischemic region of 35 mm. The increment was larger for the 50 mm region, in which Vindex approximately doubled. On the other hand, ischemia at LCX resulted in small changes of V-index of about 2 ms for both region sizes $(p < 0.05)$. The study showed that the V-index depended on the ischemic location, its size and electrophysiological changes of APs.