Continuous localization of ectopic left ventricular activation sites by means of a two-dimensional representation of body surface QRS integral maps

By means of Karhunen-Loeve transformation it is possible to represent electrocardiographic body surface QRS integral maps using only two coefficients while retaining more than 80% of information. These coefficients are computed for a number of mean paced QRS integral maps, which were acquired from well-defined ventricular segments and are contained in a database used for localization of the origin of ventricular tachycardia. It is shown that these two coefficients are sufficient to compute the pacing site in a continuous fashion, without reference to a limited number of segments. These coefficients facilitate and improve the ventricular tachycardia localization procedure based on using the database of paced QRS integral maps, by establishing the relation between QRS integral map and corresponding site of origin.