Influence of chronic myocardial infarction on exit site localization of ventricular tachycardia using paced body surface map databases

The exit site of a ventricular tachycardia can be estimated using a multichannel surface ECG, by comparing the QRS integral map of the ECG to a database of paced QRS integral maps. In the presence of chronic myocardial infarction, an appropriate database must be chosen; different databases exist for different infarct locations, because the scar tissue changes the activation wavefront propagation. Using a recently developed method to interpolate in these ECG databases, the differences between patients with and without an infarct scar are quantified. Knowledge of these differences helps one to judge how detrimental it is for localization of VT if a wrong database is chosen, and may help to create a localization algorithm that provides a more accurate estimate in an individual patient when information is present on the size and position of the infarct scar. The results show that differences are clearly present, but limited and well-behaved