Bipolar Radiofrequency Ablation of Septal Ventricular Tachycardia Facilitated by an Intramural Catheter

Figures

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  Figure 1. Cardiac Magnetic Resonance Imaging Scan and Implantable Cardioverter-Defibrillator Interrogation Cardiac magnetic resonance performed before cardiac resynchronization therapy-defibrillator implantation demonstrating midmyocardial scarring (white arrows) in the basal septum to midseptum seen in (A) short-axis and (B) apical 4-chamber views. (C) Sustained monomorphic ventricular tachycardia (cycle length 280 ms) treated by antitachycardia pacing. Note the similarity of the far-field electrograms of the clinical ventricular tachycardia to those produced during antitachycardia pacing delivered from the septal implantable cardioverter-defibrillator lead: (top) atrial electrogram, (middle) ventricular electrogram, (bottom) cardiac resynchronization therapy-defibrillator marker channel.

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  Figure 2. Intra-Procedural Imaging and Electrogram Analysis Fluoroscopic images in the (A) left anterior oblique and (B) right anterior oblique projection showing catheter locations during the case. The 2-F octapolar catheter (white arrows in A and B) is positioned in the summit communicating vein. The HD Grid (Abbott Laboratories) is on the adjacent septal surface of the left ventricular cavity. (C) Bipolar voltage map of the left ventricular and left ventricular endocardium in the left anterior oblique projection. Areas of low voltage (<1.5 mV) are seen at the basal-septal left ventricular and periaortic regions, extending toward the apex. The HD Grid is seen within the left ventricular cavity abutting the septum. The 2-F octapolar catheter (white arrows) is also observed in the summit communicating vein extending intraseptally. (D) Fractionated and delayed electrograms (blue arrows) recorded by the 2-F octapolar catheter during sinus rhythm are significantly more prominent than those on the HD Grid situated on the adjacent left ventricular septal surface.

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  Figure 3. Catheter Ablation of Intramural Septal Substrate (A) Brief nonsustained ventricular tachycardia with a left bundle branch block–left inferior axis configuration induced by programmed stimulation. Diastolic potentials (blue arrows) are observed on the 2-F octapolar electrodes. (B) Fluoroscopic image in the left anterior oblique projection showing catheter locations immediately before bipolar ablation. Note the 2-F octapolar catheter immediately between the active ablation catheter (on septal left ventricular endocardium) and the ground electrode (on septal right ventricular endocardium). (C) Pacing from the intraseptal 2-F octapolar catheter, at 10 mA/2ms, during ablation. Initially there is capture, but after the sixth beat, loss of capture is seen. (D) Final ablation lesion set.