A 2F epicardial electrode–guided ablation from left coronary cusp for substrates of left ventricular summit tachycardia

Figures

• 

  Figure 1. Patient #1: Sustained monomorphic ventricular tachycardia exhibited right bundle branch block–like pattern (monophasic R in V1), positive concordance, and right inferior axis. Initial q wave was noted in lead I (arrow). Cycle length (CL) = 414 ms. QRS duration (QRSd) = 170 ms. Intrinsicoid deflection time in V2 = 160 ms. Maximum deflection index (MDI) = 0.69. Patient #2: Sinus rhythm with frequent ventricular premature contractions (VPCs) manifesting left bundle branch block–like pattern (qrS complex in V1, R/S transition in V2) and inferior axis. QRS duration = 140 ms. Intrinsicoid deflection time in V2 = 79 ms. MDI = 0.56. The first beat of VPCs was fusion.

• 

  Figure 2. Right and left anterior oblique fluoroscopic views depicting position of 2F catheter in the small tributaries of the great cardiac vein in the vicinity of left ventricular summit and tip of ablation catheter above (patient #1) and under (patient #2) the left coronary cusp. ABL 1-2 = distal bipolar electrode of the ablation catheter; CSd 1-2 = distal bipolar electrode of the 2F catheter.

• 

  Figure 3. Patient #1: Epicardial local abnormal ventricular activities (LAVAs; red star) displayed at CSd 1-2 as presystolic potentials 60 ms preceding QRS onset distinct from far-field ventricular signal during ventricular tachycardia and split late potentials (blue star) during sinus rhythm. Pace mapping from CSd 1-2 yielded good pace map score with S-QRS identical to LAVAs-to-QRS interval. LAVAs were not seen at the tip of ablation catheter and pace mapping did not produce a good pace map score. Epicardial LAVAs were delayed and then abolished after radiofrequency (RF) ablations. Patient #2: Epicardial LAVAs (red star) displayed at CSd 1-2 as presystolic potentials 78 ms preceding QRS onset during ventricular premature contractions (VPCs) distinct from the far-field ventricular signals. Late potentials during sinus rhythm had 2 components: initial fractionated signals buried in far-field ventricular potentials and split late spiky signals. LAVAs were not seen at the tip of the ablation catheter. Pace mapping from CSd 1-2 and left coronary cusp (LCC) produced similar, but not identical, QRS configuration to VPCs. After RF ablations, late potentials became 2:1, delayed, and completely…