New implications for the recurrence mechanism of an upper septal ventricular tachycardia: A case report

Abstract

Background Verapamil-sensitive fascicular ventricular tachycardia (VT) is the most common type of idiopathic left ventricular tachycardia, and it is divided into three types. Upper septal ventricular tachycardia (US-VT) is likely in patients with prior episodes of left posterior fascicular (LPF)-VT ablation, however, little is known about the recurrence mechanism of US-VT. Case summary A 53-year-old man had an US-VT after two catheter ablation sessions for a common idiopathic LPF-VT. The USVT was successfully treated by ablating the proximal site of the LPF without making any further branch or fascicular block. This successful ablation point corresponded completely with the earliest pre-systolic potential (P2) site of the LPF-VT during the 1st session of catheter ablation. Discussion An US-VT recurrence could occur if a critical slow conduction is not affected by the catheter ablation. This recurrence might be the result of changing the re-entrant circuit after damage to the LPF. In order to eliminate the LPFVT and prevent an US-VT recurrence, the earliest P2 site should be investigated carefully and ablated sufficiently.