Scar-related reentrant ventricular tachycardia (VT) may be present in a variety of structural heart disease (SHD) phenotypes. In this setting, VT circuits are comprised of viable myocytes separated by fibrosis, allowing for the slow conduction needed to facilitate reentry.1,2 Aetiologies of fibrosis include ischaemic heart disease (IHD), inflammatory conditions, infiltrative cardiomyopathy, dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy and arrhythmogenic right ventricular (RV) dysplasia.Implantable cardioverter defibrillators (ICDs) are the mainstay of therapy for the prevention of sudden cardiac death in patients with SHD.3 However, ICD shocks are associated with diminished quality of life and increased mortality.4-6 Anti-arrhythmic drugs (AADs) have an important role in shock reduction; however these agents often have limited efficacy and significant side-effects. 7,8 Catheter ablation has assumed an increasingly important role in the management of VT. In patients with IHD and drug-refractory VT, ablation has been shown to reduce arrhythmia recurrence and ICD therapies.
9-11Patients who have VT rendered non-inducible by an ablation procedure have a lower VT recurrence rate and mortality compared with those who still have inducible arrhythmias after the ablation.12 Catheter ablation has also been shown to be effective in the treatment of VT storm in patients with SHD receiving chronic AAD therapy.
13In the setting of non-ischaemic SHD, catheter ablation outcome varies according to the nature of the underlying heart disease, with a greater need for epicardial mapping and ablation, higher recurrence rate and more AAD use in long-term follow-up.14-16 For the most part, VT ablation remains underutilised and some patients may benefit from earlier intervention.
17Although ablation also has an important role in the management of patients with idiopathic VT, this review will focus on ablation of scarrelated reentrant VT, the most common mechanism of monomorphic VT in patients with SHD.
Pre-procedural PlanningHeart failure optimisation is important for decreasing the risk of
Electrocardiographic CharacterisationTwelve-lead electrocardiograms (ECGs) of all clinical VTs are important in localising VT exit sites, identifying potential ablation targets and directing the best ablation strategy including possible epicardial access.In the setting of non-ischaemic IHD, morphological criteria suggesting Abstract Scar-related reentry is the most common mechanism of monomorphic ventricular tachycardia (VT) in patients with structural heart disease. Catheter ablation has assumed an increasingly important role in the management of VT in this setting, and has been shown to reduce VT recurrence and implantable cardioverter defibrillator (ICD) shocks. The approach to mapping and ablation will depend on the underlying heart disease etiology, VT inducibility and haemodynamic stability. This review explores pre-procedural planning, approach to ablation of both mappable and unmappable VT, and post-procedural testing. Future de...