Development and evaluation of 12-lead electrocardiogram in the left free wall of accessory pathway localization in patients with typical Wolff-Parkinson-White syndrome

Objectives: This study was designed to characterize 12-lead electrocardiogram (ECG) for localization of the left free wall lateral accessory pathway (AP) in patients with typical Wolff-Parkinson-White (WPW) syndrome, to develop a new algorithm ECG for localizing APs, and to test the accuracy of the algorithm prospectively. Method: We studied 129 patients; 84 patients had typical WPW syndrome with single anterograde AP identified by successful radiofrequency catheter ablation (RFCA), and were enrolled to build a new ECG algorithm for localizing left free wall APs. Then, the algorithm was tested prospectively in 45 patients and compared with the location of APs successfully ablated by RFCA. Results: We found that the 12-lead ECG parameters in typical WPW syndrome, such as delta wave polarity in V1, R/S ratio in V1, transition of the QRS complex, and delta wave polarity in inferior, lead to diagnosis and localization of APs, with highest accuracy predicted from 74.5%-100%, and for development of a new ECG algorithm. From the 45 patients who were prospectively evaluated by the newly derived algorithm for the left free wall pathways, the sensitivity and specificity was high (from 75-100%). Conclusion: The 12-lead ECG parameters in typical WPW syndrome are closely related to left free wall AP localization and can be used to develop a new ECG algorithm by the parameters above. Moreover, the new ECG algorithm can predict the location of APs with high accuracy.