Bipolar radiofrequency ablation for re-entrant ventricular tachycardia of right bundle branch block and left bundle branch block morphologies with the common slow conduction zone at the left ventricular summit: a case report.

Background: The left ventricular (LV) summit has anatomical limitations, so the detailed mapping is difficult. Therefore, the mechanism of ventricular tachycardia (VT) originating from the LV summit is not well understood. Case summary: A 70-year-old man had VTs with right bundle branch block (VT1 and VT3) and left bundle branch block (VT2) morphologies originating from the left ventricular summit (LV summit). During the VT2 and VT3, fragmented potentials, which occurred earlier than the QRS onset, were recorded from bipolar electrodes of a catheter at the anterior intraventricular vein (AIV). By pacing from right ventricular apex, constant and progressive fusion were observed. During the entrainment pacing, the fragmented potentials in the AIV catheter were activated orthodromically and those in the His bundle were activated antidromically. In addition, there were two components of the ventricular electrogram at the LV summit area with the interval of more than 100 ms during the VTs. We performed bipolar radiofrequency ablation between the LV endocardium and AIV, and the VTs became non-inducible. Discussion: Non-sustained VT/premature ventricular contraction originating from LV summit is generally considered to occur due to abnormal automaticity or triggered activity. In contrast, using entrainment technique, we demonstrated that the VTs with multiple morphologies were sustained with a re-entrant mechanism. Fragmentated potentials recorded in the AIV catheter were activated orthodromically with the entrainment pacing, indicating the slowly conducting isthmus. The intramural VT substrate was also suggested with a prolonged conduction time between the two ventricular components during the VTs.

Successful Application of Stereotactic Body Radiation Therapy for Ventricular Tachycardia Substrate in a Patient With Nonischemic Cardiomyopathy.

Cardiac stereotactic body radiotherapy (SBRT) has been gaining attention as a potential treatment for patients with ventricular tachycardia (VT). Here, we describe a nonischemic patient with severe heart failure and VTs originating from the deep anteroseptal substrate that was refractory to standard and bipolar catheter ablations, and was successfully managed with SBRT. In conclusion, anteroseptal VTs resistant to catheter ablation in severe nonischemic heart failure might be an indication for cardiac SBRT as palliative therapy.

Dual countertraction for extraction of abandoned leads with severe lead-to-lead adhesion.

Note that firm adhesion between the atrial lead near the proximal electrode and the ventricular lead is present. Simultaneous application of countertraction from the femoral and jugular workstation, i.e. dual countertraction, liberated the two leads from the adhesion.

A single premature stimulation from the para-Hisian region unmasked negative involvement of the left anterior fascicle in the verapamil-sensitive ventricular tachycardia with a right bundle branch block and right-axis deviation.

A 33-year-old man had verapamil-sensitive ventricular tachycardia (VT) with a right bundle branch block (RBBB) and right axis deviation. Programmed stimulation from the para-Hisian region induced ventricular tachycardias (VT1 or VT2). VT1 was entrained during pacing from the para-Hisian region. A single para-Hisian stimulation antidromically captured the proximal portion of the left anterior fascicle (LAF), but the cycle length of VT2 remained unchanged. This observation indicated that the upper limb of the LAF was a bystander of the reentry circuit. We have clarified this mechanism with applying a single premature stimulation from the para-Hisian region.