Purpose of Review
Ventricular arrhythmias (VAs) are a significant cause of morbidity and mortality in patients with cardiomyopathy (CM). This review focuses on ventricular tachycardia (VT) management in uncommon causes of heart disease, such as inflammatory and infiltrative CMs.
Recent Findings
Integration of advanced cardiac imaging modalities, such as cardiac magnetic resonance imaging (MRI) and positron emission tomography (PET), into diagnostic evaluation of patients with CM may unmask abnormal myocardial substrate in almost half of patients presenting with VAs. Stepwise approach to management of VAs in cardiac sarcoidosis (CS) includes use of immunosuppressive therapy during active inflammatory phase and reserves radiofrequency catheter ablation (RFCA) for later fibrotic phase of the disease. Recurrences of VT are common, but reduction in VA burden can be achieved in up to 90% of patients after RFCA. VAs in patients with acute nonchagasic myocarditis often resolve with supportive therapy and treatment of heart failure. RFCA in chagasic myocarditis is typically used for patients with sustained monomorphic VT who do not respond to antiarrhythmic medications. Basal inferolateral scar is a common arrhythmia substrate, while at least a third of reentrant circuits are epicardial. Upfront combined epicardial and endocardial approach should be considered in all patients with chagasic myocarditis. VAs in cardiac amyloidosis tend to be focal and respond well to catheter ablation. VT substrate in Fabry disease is similar to other forms of non-ischemic CM with the predilection for perivalvular, basal lateral left ventricle, as well as epicardial location.
Summary
In patients with inflammatory and infiltrative CM, RFCA is an important treatment modality that reduces recurrent VT episodes and ICD shocks. Initial work-up with cardiac MRI and PET prior to consideration of ablation can be invaluable in diagnosing etiology of non-ischemic CM and to better gear treatment. Neuromodulation, including bilateral cardiac sympathetic denervation can reduce burden of arrhythmias in some patients with refractory VT, though additional studies are needed.