Clinical application of an integrated 3-phase mapping technique for localization of the site of origin of idiopathic ventricular tachycardia

Background-Radiofrequency (RF) catheter ablation provides curative treatmen t for idiopathic ventricular tachycardia (VT). Methods and Results-Nineteen consecutive patients with an idiopathic VT und erwent RF catheter ablation. An integrated 3-phase mapping approach was use d, consisting of-the successive application of online 62-lead body surface QRS integral mapping, directed regional paced body surface QRS integral map ping, and local activation sequence mapping. Mapping phase 1 was localizati on of the segment of VT origin by comparing the VT QRS integral map with a database of mean paced QRS integral maps. Mapping phase 2 was body surface pace mapping during sinus rhythm in the segment localized in phase 1 until the site at which the paced QRS integral map matched the VT QRS integral ma p was identified (ie, VT exit site). Mapping phase 3 was local activation s equence mapping at the circumscribed area identified in phase 2 to identify the site with the earliest local endocardial activation (ie, site of VT or igin). This site became the ablation target. Ten VTs were ablated in the ri ght ventricular outflow tract, 2 at the basal LV septum, and 7 at the midap ical posterior left ventricle. A high long-term ablation success (mean foll ow-up duration, 14+/-9 months) was achieved in 17 of-the 19 patients (89%) with a low number of RF purses (mean, 3.3 +/- 2.2 pulses per patient). Conclusions-This prospective study shows that integrated 3-phase mapping fo r localization of the site of origin of idiopathic VT offers efficient and accurate localization of the target site for RF catheter ablation.