AUTOMATIC QRS ONSET AND OFFSET DETECTION FOR BODY-SURFACE QRS INTEGRAL MAPPING OF VENTRICULAR-TACHYCARDIA

A QRS onset and offset detection algorithm has been developed for use in body surface QRS integral mapping of ventricular tachycardia. To de termine QRS intervals, the algorithm uses two computed signals: the su m of the absolute values of the first derivatives of all leads and the sum of the absolute values of all leads. The second order derivative of the latter parameter is used to detect the time instants of QRS ons et and offset. Using the algorithm, QRS integral maps are subsequently computed, which are correlated with a database of QRS integral maps i n order to localize the site of origin of ventricular tachycardia. Com parison of the performance of the algorithm with visual evaluation by a human expert in this procedure revealed, in 95% of the cases, an ide ntical or adjacent localization of the site of origin.