Is the 12-lead electrocardiogram during antidromic circus movement tachycardia helpful in predicting the ablation site in atriofascicular pathways?

Aims Unlike in the Wolff-Parkinson-White syndrome, there has been no systematic study on the role of the pre-excitation pattern in predicting the ablation site in patients with atriofascicular (AF) pathways. We assessed in a large cohort the value of the 12-lead electrocardiogram (ECG) during antidromic tachycardia (ADT) to predict the site of ablation. Methods and results Forty-five patients were studied, 23 males (51%), mean age of 27 +/- 12 years with 46AF pathways and 48 ADT using the AF pathway for A-V conduction. Inclusion required induction of a sustained ADT and successful ablation. Ablation site was assessed during LAO45 degrees projection and clockwise classified as hours in posteroseptal, posterolateral, lateral, anterolateral, and anteroseptal tricuspid annulus as follows: 05:00-07: 00,>07: 00-08:00, >08: 00-09:00,>09:00-11:00, and >11:00-13: 00 o'clock. The QRS axis was assessed during ADT and classified as normal (>+15 degrees), horizontal (+15 degrees to -30 degrees), and superior (