Left posterior fascicular ventricular tachycardia associated with a septal fissure complicated by iatrogenic ventricular septal defect: a case report

Abstract Background Left posterior fascicular ventricular tachycardia (LPF-VT) is considered the most common type of fascicular ventricular tachycardia. False tendons (FTs) are reported to be common in patients with LPF-VT and may contribute to the pathogenesis of this condition. However, LPF-VT cases with congenital septal structural abnormalities have not been reported. Case summary This case report investigated an 86-year-old woman diagnosed with LPF-VT and underwent radiofrequency ablation. The preoperative transthoracic echocardiography (TTE) results indicated no anatomic abnormalities. During the procedure, the intracardiac echocardiography (ICE) revealed a fissure within the ventricular septum. The successful ablation site was precisely located at the left orifice of this fissure. To improve treatment efficacy, the catheter was advanced into the fissure to continue ablation. One month postoperation, the patient presented with mild shortness of breath after activity. The TTE revealed a 15 × 16-mm iatrogenic ventricular septal defect (VSD) with a pulmonary artery pressure (PAP) of 48 mmHg. Percutaneous VSD closure resolved the symptoms, and the PAP returned to normal. During the follow-up period, no recurrence of palpitations or dyspnea was observed. Discussion Macro-reentry has been suggested as the mechanism of LPF-VT, as FTs can provide an electro-anatomical substrate for LPF-VT. In the present case, the re-entrant circuit of LPF-VT may be associated with the rare anatomic anomaly, although a definitive link remains unestablished. Additionally, extreme caution should be exercised during catheter manipulation to prevent iatrogenic injuries.