Lines, circles, channels, and clouds: looking for the best design for substrate-guided ablation of ventricular tachycardia

This editorial refers to ‘Electrical isolation of substrate after myocardial infarction: a novel ablation strategy for unmappable ventricular tachycardias—feasibility and clinical outcome’ by R. R. Tilz et al ., on page 1041 .Radiofrequency (RF) catheter ablation of ventricular tachycardia (VT) has become an important part of the therapeutic armamentarium for treating ventricular arrhythmias in patients with structural heart disease.1 Catheter ablation has proven to control arrhythmic storm and reduce shocks in implantable cardioverter-defibrillator (ICD) recipients with ventricular arrhythmia episodes.2Novel VT catheter ablation techniques have been developed to overcome the limitations of conventional mapping and ablation. These new techniques aim to characterize and eliminate the arrhythmogenic substrate during stable rhythms. In addition, the advent of three-dimensional non-fluoroscopic systems that allow a detailed electroanatomic reconstruction of the ventricles has facilitated the development of substrate-guided ablation. However, despite improvements in the ablation technology, the rate of recurrence after ablation remains high.3Based on the surgical experience, Marchlinski et al .4 proposed targeting scar border zone tissue areas with bipolar voltage from 0.5 to 1.5 mV. The best ablation design was considered the creation of ‘linear ablation lines’ transecting the dense scar (<0.5 mV) until reaching the normal myocardium or valve continuity. Pacemapping was used to reduce RF application.4,5Different markers of VT isthmus have been identified during sinus or paced rhythms and have been proposed as …