Clinical Outcomes After Catheter Ablation in Cardiac Sarcoidosis and Idiopathic Nonischemic Cardiomyopathy

Introduction Cardiac sarcoidosis (CS) may present clinically with ventricular tachycardia (VT). Since the diagnosis is challenging, clinical manifestations and imaging findings are commonly used to identify probable CS in patients without histological diagnosis or extracardiac sarcoidosis. However, data on VT ablation with probable CS remains limited. We investigated the scar distribution and long‐term outcomes of VT ablation in patients with at least probable CS and compared these with noninflammatory nonischemic cardiomyopathy (NICM) patients. Methods and Results Patients with at least probable CS and VT, who underwent catheter ablation were retrospectively included (the CS group), and compared with idiopathic NICM patients in whom focal inflammation was excluded via fluorodeoxyglucose‐positron emission tomography (the noninflammatory NICM group). Procedural characteristics including scar distribution data along with postprocedural clinical outcomes were assessed. Twenty‐three and 40 patients were included in the CS and noninflammatory NICM groups, respectively. Left and right ventricular substrate mapping was performed in 48% and 57% of CS patients, and in 68% and 38% of noninflammatory NICM patients. Right ventricular map revealed a broader bipolar low‐voltage area and a more frequent unipolar low‐voltage area in the septum in the CS group, whereas left ventricle map demonstrated no significant differences. At 1‐year, ventricular arrhythmia‐free survival (48% vs. 85%, p = 0.01, after multiple procedures) and death/transplant‐free survival were lower in the CS group (54% vs. 97%, p < 0.01). Conclusion CS patients exhibited significantly worse outcomes after VT ablation, compared to noninflammatory NICM patients, highlighting the importance of distinguishing CS from idiopathic NICM to optimize patient management.