A single premature stimulation from the para-Hisian region unmasked negative involvement of the left anterior fascicle in the reentrant circuit of verapamil-sensitive ventricular tachycardia with a right bundle branch block and right-axis deviationMasahiro Toba, MDa, Toshihiro Nasu, CEb, Nobuyoshi Nekomiya, CEb, Ryo Itasaka, CEb, Takao Makino, MDa, Hisashi Yokoshiki, MD, PhDaaDepartment of Cardiovascular Medicine, Sapporo City General Hospital, Sapporo, JapanbDivision of Medical Engineering Center, Sapporo City General Hospital, Sapporo, JapanShort title : A single premature stimulation from the para-Hisian region unmasked negative involvement of the left anterior fasciculeAddress for correspondence :Masahiro Toba, M.D.E-mail: masahiro-toba@doc.city.sapporo.jpHisashi Yokoshiki MD, PhDDepartment of Cardiovascular Medicine, Sapporo City General Hospital, Kita-11, Nishi-13, Chuo-ku, Sapporo 060-8604, Japan.Phone: 81-11-726-2211Fax: 81-11-726-7912E-mail: hisashi.yokoshiki@doc.city.sapporo.jpKey Words : verapamil-sensitive ventricular tachycardia, the left anterior fascicle, reentry, single premature stimulation, para-Hisian region, radiofrequency ablation

A left bundle branch block morphology tachycardia with fragmented potentials at the His bundle area Masahiro Toba, MDa, Toshihiro Nasu, CEb, Nobuyoshi Nekomiya, CEb, Ryo Itasaka, CEb, Takao Makino, MDa, Hisashi Yokoshiki, MD, PhDaaDepartment of Cardiovascular Medicine, Sapporo City General Hospital, Sapporo, JapanbDivision of Medical Engineering Center, Sapporo City General Hospital, Sapporo, JapanAddress for correspondence :Hisashi Yokoshiki MD, PhDE-mail:hisashi.yokoshiki@doc.city.sapporo.jpDepartment of Cardiovascular Medicine Sapporo City General Hospital, Kita-11, Nishi-13, Chuo-ku, Sapporo 060-8604, Japan.Phone: 81-11-726-2211Fax: 81-11-726-7912Key words : longitudinal dissociated his bundle, left bundle branch block morphology tachycardia, fragmented potentials, radiofrequency ablation

We described a 15-year-old boy who underwent the catheter ablation for the nodoventricular tachycardia that had difficulty in differentiation from atrioventricular nodal reentrant tachycardia with upper common pathway. The slow pathway ablation revealed an anterograde conduction of nodoventricular fiber. We successfully performed the catheter ablation targeting for the right ventricular insertion site of the nodoventricular fiber.

Aims Non-sustained ventricular tachycardia (NSVT) occurs frequently in patients with dilated cardiomyopathy (DCM), especially in high-risk patients. The role of rapid-rate NSVT (RR-NSVT) documented by an implantable cardioverter defibrillator (ICD) in DCM patients has not been fully explored. This study aimed to determine the relationship between RR-NSVT and the occurrence of ventricular tachyarrhythmias (VTAs) in DCM patients with ICD. Methods From December 2000 to December 2017, 136 DCM patients received ICD or cardiac resynchronization therapy defibrillator (CRT-D) implantation for primary or secondary prevention of VTAs. Based on the occurrence of documented RR-NSVT, patients were classified into RR-NSVT (-) or RR-NSVT (+) groups. Result During the median follow-up of 4.5 years, 50.0% (68/136) of patients experienced ≥ 1 episode, and 25.0% (34/136) of patients experienced ≥ 3 episodes of RR-NSVT. Event-free survival for VTAs was significantly higher in the RR-NSVT (+) group whereas those for heart failure admission and cardiovascular mortality were comparable between groups. In the multivariate cox regression analysis, any RR-NSVT showed a positive association with the occurrence of VTAs (HR: 5.087; 95% CI: 2.374-10.900; p<0.001). In RR-NSVT (+) patients, a cluster (≥ 3 times/6 months) and frequent pattern (≥ 3 runs/day) of RR-NSVT were observed in 42.6% (29/68) and 30.9% (21/68) of patients, respectively, who showed further increased incidence of VTAs. Conclusion In DCM patients with ICD/CRT-D, 50.0% experienced at least 1 episode of RR-NSVT. RR-NSVT documentation showed a positive association with subsequent occurrence of VTAs, suggesting the importance of constructive arrhythmia management for patients with RR-NSVT.