Long-Term Outcome After Catheter Ablation For Left Posterior Fascicular Ventricular Tachycardia Without Development Of Left Posterior Fascicular Block

Background:Idiopathic left ventricular tachycardia (ILVT) predominantly presents in young patients without structural heart disease[1-4]. The most common subtype, left posterior fascicular ventricular tachycardia (LPFVT), typically presents with right bundle-branch block (RBBB) morphology and superior axis. According to recent studies, reentry is the underlying mechanism with an excitable gap and a slow zone of conduction. The arrhythmogenic substrate is located at the posterior aspect of the mid-septal region involving the Purkinje network of the left posterior fascicle. Catheter ablation of left posterior fascicular ventricular tachycardia (LPFVT) is commonly performed during tachycardia. End point of RF ablation was noninducibility of tachyarrhythmia and without Left Posterior Fascicular Block following ablation. This study reports on the long-term outcome of patients undergoing ablation of LPFVT targeting the earliest retrograde activation within the posterior Purkinje fiber network during sinus rhythm (SR).Objective:This study reports on the long-term outcome of patients undergoing ablation of LPFVT targeting the earliest retrograde activation within the posterior Purkinje fiber network without development of left posterior fascicular block during sinus rhythm (SR).Methods:This study retrospectively analyzed data from60consecutive patients (23female; mean age27±12years) with symptomatic, electrocardiographically documented LPFVT referred for EPS and radiofrequency ablation. Programmed ventricular stimulation was performed from the right ventricular apex. It was confirmed Left Posterior Fascicular Ventricular Tachycardia by EPS. Catheter ablation targeted the earliest potential suggestive of retrograde activation within the posterior Purkinje fiber network (retro-PPs) recorded along the posterior mid-septal left ventricle during SR. Radiofrequency current was delivered for a maximum of120seconds in temperature-controlled mode with a cut-off of55℃and30W. Endpoint of RF ablation was noninducibility of tachyarrhythmia following ablation and without Left Posterior Fascicular Block.Results:Among all these60patients with left posterior fascicular ventricular tachycardia, at time of EPS, clinical VT was inducible in48(80%) patients under sedation with programmed ventricular stimulation or/and isoproterenol infusion. In12of60(20%) patients, clinical VT was noninducible during EPS despite the use of isoproterenol. All patients accept catheter ablation targeted the earliest potential suggestive of retrograde activation within the posterior Purkinje fiber network recorded along the posterior mid-septal left ventricle during SR. Median procedure duration was240(range85-345) minutes with a median of4(2-15) RF applications. There were42patients without Left Posterior Fascicular Block and were18patients have Left Posterior Fascicular Block. No complications related to ablation. Long-term follow-up data were obtained from outpatient clinic visits, and telephone interviews with all patients. After a median follow-up period of8.5(4.5-10.5) years,56(93%) patients were free from recurrent VT. Conclusions:In patients presenting with LPFVT, this study demonstrates that substrate-based mapping and ablation targeting the earliest retro-PPs during SR is highly successful, resulting in excellent long-term clinical outcome without development of inadvertent Left Posterior Fascicular block during ablation.