A Moving Target for Catheter Ablation of Ventricular Tachycardia: Ablation of Scar or Arrhythmia?

SEE PAGE 2872 C atheter ablation of ventricular tachycardia (VT) reduces recurrent VT across multiple clinical settings, from electrical storm to pre-emptive therapy after a first occurrence of VT (1). Approaches for ablation include targeting the arrhythmia using electrophysiological approaches (entrainment mapping, pacemapping, and electroanatomic mapping) and substrate modification to reduce the arrhythmogenicity of a scar. Superiority of a single approach has not been demonstrated consistently, although recent trends associate more extensive ablation with less VT recurrence (2–4). There is inconclusive evidence that mapping during VT improves long-term ablation success compared with a substrate-based approach in sinus rhythm (5,6). “Substrate-based” approaches use electroanatomic mapping to carry out ablation predominantly during sinus rhythm and have variable, operator-dependent interpretations. Although many centers undertake a refined search for an induced VT morphology, others ablate the scar without any specific arrhythmia targeting. The rationale for the latter approach is that more extensive tissue destruction is necessary to emulate surgical resection. Furthermore, most patients have multiple VTs and the search for a single isthmus may be distracting and time-consuming. The counter argument is that not all low-voltage regions are critical components of re-entrant circuits, and methods that identify the most arrhythmogenic areas