Successful Ablation of Moderator Band-Originated Ventricular Tachycardia at Its Ventricle Insertion Sites

MB-originated ventricular tachycardia or ventricular fibrillation (VT/VF) is a kind of idiopathic malignant arrhythmia in the absence of structural heart disease, which is frequently triggered by a premature ventricular contraction (PVC) from the same site. Frequent unifocal PVC was observed, and the PVC showed a left bundle branch block (LBBB) pattern with precordial transition later than V4 [Figure 1]a, some of which precipitated recurrent episodes of VT [Figure 1]b. Moreover, some of the PVC-induced VF that was restored to sinus rhythm through electrical cardioversion [Figure 1]c and implantable cardioverter-defibrillator (ICD, Lumax 340 VR, BIOTRONIK SE & Co. KG, Berlin, Germany) was implanted for the secondary prevention of sudden cardiac death (SCD). RF current was delivered separately to the free wall and septum insertions of MB [Figure 1]e and [Figure 1]f. The RF energy was applied using a power-controlled mode with a delivered power up to 35 W and the tip temperature of 43C for 15-60 s per site with contact force ranging from 9 to 31 g. The patient underwent an uneventful procedure with normal baseline 12-lead ECG and echocardiography and did not require antiarrhythmic drugs postablation.