Background: The anatomical substrate for left posterior fascicular ventricular tachycardia (LPF-VT) is still unclear.
Objectives: The purpose of this study is to describe the endocavitary substrate of the re-entrant loop of LPF-VT.
Methods: A total of 26 consecutive patients with LPF-VT underwent an electrophysiology study and radiofrequency ablation.
Results: Intracardiac echocardiography imaging observed a 100% prevalence of false tendons (FTs) at the left posterior septal region in all patients, and 3 different types of FTs could be classified according to their location. In 22 patients, a P1 potential could be recorded via the multielectrode catheter from a FT. In 4 patients without a recorded P1 during LPF-VT, the earliest P2 potentials were recorded from a FT in 3 patients, and from a muscular connection between 2 posteromedial papillary muscles in 1 patient. Catheter ablation focused on the FTs with P1 or earliest P2 (in patients without P1) was successful in all 26 patients. After 19 ± 8.5 months of follow-up, no patients had recurrence of LPF-VT.
Conclusions: FTs provide an electroanatomical substrate for LPF-VT and a "culprit FT" may be identified as the critical structure bridging the macro-re-entrant loop. Targeting the "culprit FT" is a novel anatomical ablation strategy that results in long-term arrhythmia-free survival.
Keywords: false tendon; left posterior fascicular tachycardia; radiofrequency ablation; ventricular tachycardia.
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