Catheter and Device Management of Inherited Cardiac Conditions

This state-of-the art review discusses sudden cardiac death (SCD) risk stratification and prevention using implantable cardioverter defibrillator (ICD) therapy and the place of catheter ablation in the major inherited cardiomyopathies and primary arrhythmic syndromes. ICD therapy protects against SCD in many inherited cardiac conditions, particularly the cardiomyopathies in advanced stages, such as hypertrophic cardiomyopathy (HCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC). However, they are not usually indicated in most patients with cardiac ion channelopathies, particularly long QT syndrome, since medical management is safe and preferable for most cases. The general exception is the secondary prevention setting following a cardiac arrest, where guidelines mostly support ICD therapy. However, in the case of catecholaminergic polymorphic ventricular tachycardia (CPVT), ICD therapy is less clear, with some studies indicating increased mortality when an ICD is used following a cardiac arrest, compared to optimal medical therapy alone. When ICDs are placed, they are commonly associated with morbidity, and do not reduce the burden of ventricular arrhythmias (VA), such that multiple ICD shocks can ensue. Catheter ablation has been shown to reduce VA burden, VA related symptoms and ICD therapy in correctly identified patients in each condition. Its role is particularly important in cases where monomorphic ventricular tachycardia (VT) is prevalent, such as Lamin-related dilated cardiomyopathy (DCM) and ARVC. Evidence is growing to support the use of catheter ablation to treat premature ventricular contraction (PVC) induced VF in the setting of long and short QT syndromes, CPVT, idiopathic VF and early repolarisation syndromes. In Brugada syndrome, epicardial substrate ablation can even apparently eliminate the electrocardiographic (ECG) phenotype and reduce VA burden during follow-up.