A NEW ECG ALGORITHM FOR THE LOCALIZATION OF ACCESSORY PATHWAYS USING ONLY THE POLARITY OF THE QRS COMPLEX

A new algorithm is proposed for localization of accessory atrioventric ular pathways by use of a 12-lead electrocardiogram (ECG). The polarit y of the QRS complex in leads III, V-1, and V-2 from 102 patients with Wolff-Parkinson-White syndrome with manifested preexcitation who unde rwent successful radiofrequency catheter ablation was analyzed. Access ory pathways on the right side of tile heart were localized to three r egions around the tricuspid annulus, and left-sided pathways were loca lized to two regions around the mitral valve annulus. In 42 of 46 pati ents (91%) with left posterolateral accessory pathways, a common chara cteristic of the ECG was a positive QRS complex in leads III and V-1 ( sensitivity 91%, specificity 95%). of 19 patients with left inferior p araseptal or inferior accessory pathways, 16 (84%) had a negative QRS complex in lead III and a positive QRS complex in lead V-1 (sensitivit y 84%, specificity 98%). All six patients with right anterosuperior pa raseptal accessory pathways had a positive QRS complex in lead III but a negative QRS complex in lead V-1 (sensitivity 100%, specificity 97% ). The 25 patients with light inferior paraseptal or inferior accessor y pathways had a negative or isodiphasic QRS complex in leads III and V-1, but the QRS complex was positive in lead V-2 in 21 (84%) of these patients (sensitivity 84%, specificity 100%). Finally, five of the si x patients (83%) with right anterior accessory pathways had a negative QRS complex in leads III, V-1, and V-2 (sensitivity 83%, specificity 96%). With the algorithm, the localization of accessory pathways was t hus identified in 90 of the 102 patients (88%).