Off-line analysis of electro-anatomical mapping in ventricular arrhythmias

Sudden cardiac death due to ventricular tachycardia (VT) is a major health issue in patients with structural heart disease and depressed ejection fraction. If from one side, implantable cardioverter defibrillator (ICD) therapy has significantly improved survival of these patients, on the other hand, it has led to frequent ICD shocks as an emerging problem, being associated with poor quality of life, frequent hospitalizations and increased mortality. Scar-related re-entry due to the coexistence of surviving myocardial fibers within fibrotic tissue is the most common mechanism subtending VT both in ischemic and non-ischemic cardiomyopathies. In the last two decades, continuous efforts to determine VT mechanisms and effectively prevent and treat VT with a substrate-based approach has benefit from off-line analysis of data coming from invasive electroanatomical mapping as well as from noninvasive imaging modalities such as cardiac magnetic resonance able to identify the arrhythmic substrate. In this review, we walk over again established methods for VT substrate characterization and we present possible applications of new emerging technologies.