Infarct-Related Myocardial Regions with Functional Relevance During Pacing and Ventricular Tachycardia Show Similar Underlying Substrate.

Ventricular remodeling after myocardial infarction is associated with a potential proarrhythmic substrate. However, the interplay between the structural and functional substrate for ventricular tachycardia (VT) maintenance is not completely understood. Here, we aimed to study the scar and fiber disorganization substrate associated with functional alterations during ventricular pacing and VT mapping. Fourteen pigs with infarctrelated substrate underwent state-of-the-art cardiac imaging and invasive mapping procedures to identify the functional and structural properties associated with abnormal wave-front propagation and VT maintenance. The results show that deceleration zones during ventricular pacing and critical isthmus sites during VT mapping show similar underlying scar properties and myocardial fiber disorganization. However, deceleration zones derived from one pacing location were not sufficient to identify critical VT isthmus sites in all animals.