Latest technology for scar-related reentrant VTs- Searching for the Optimal Endpoint

Ventricular tachycardia (VT) that occurs in patients with structural heart disease (SHD) carries an elevated risk for sudden cardiac death (SCD), and implantable cardioverter-defibrillators (ICDs) are the mainstay of therapy. In these individuals, catheter ablation may be used as adjunctive therapy to treat or prevent repetitive ICD therapies when antiarrhythmic drugs are ineffective or not desired. In patients with SHD, the main challenge for catheter ablation of VT is the complex arrhythmogenicity of the myocardial scar. Electroanatomical remodeling of the scar that occurs in SHDs may prompt arrhythmias through different mechanisms. Although reentry has been described as the main arrhythmia mechanism in patients with SHD, triggered activity and enhanced automaticity have also been described. The potential for myocardial scar involving the midwall and epicardial surface of the ventricles further complicates the assessment of the arrhythmic substrate. Consequently, identifying and effectively targeting the culprit areas of the myocardial scar remains a challenging task. The clinical correlation of this complex arrhythmia substrate is the high rate of VT recurrence after ablation, especially in patients with nonischemic cardiomyopathy. In order to improve the outcomes of ablation, new strategies of substrate ablation have been proposed that aim to perform selective ablation of the scar-related VT; which include “scar homogenization”, “scar dechanneling”, “core isolation”, “local abnormal ventricular activities (LAVA)”, pacemapping to identify VT isthmus, and pre-procedural imaging. These new strategies on endo- and epicardial surface have been associated with favorable outcomes; however, a potential drawback is that abnormal activity not related to arrhythmia onset and maintenance may be targeted for ablation. Moreover, the acute procedural endpoint other than non-inducibility is still unclear. In this session, we want to discuss the advantage and limitations of these new strategies and the optimal endpoint of procedure.