Background: Idiopathic left ventricular tachycardia (ILVT) is originated around the left posterior fascicle, which was targeted for radiofrequency ablation. Therefore, ventricular conduction via left posterior fascicle would be affected, and QRS morphology would be changed.
Methods: This retrospective study included 32 patients with ILVT who underwent successful ablation of ILVT between January 2005 and July 2010. QRS morphology before and after ablation were compared.
Results: The QRS morphology changes after ablation were classified into 5 categories; right axis deviation with left posterior fascicular block pattern (type 1), prominent q wave in inferior lead (type 2), prominent S wave in inferior lead (type 3), no change or disappearance of S wave in inferior lead (type 4), no change in any limb lead (type 5). The characteristics of QRS morphologies were summarized in the Table. Precordial transition showed clockwise (n=18, 56%), counterclockwise (n=1, 3%) rotation, or no transitional zone shift (n=13, 41%). Conclusion:Radiofrequency ablation of ILVT resulted in various QRS morphology changes in precordial lead as well as in limb lead. This implies that Purkinje potential-guided approach in catheter ablation of ILVT targets different branches of the left posterior fascicle.
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