Outcomes after transvenous defibrillator implantation in cardiac sarcoidosis: a systematic review

Introduction: Sarcoidosis is a systemic inflammatory disorder associated with ventricular arrhythmias (VAs) and sudden death in the context of cardiac involvement. Established guidelines advocate implantable cardioverter-defibrillator (ICD) implantation in specific subcohorts, but there is a paucity of data on outcomes. Methods: and Results We conducted a systematic review of published literature to assess outcomes in patients with cardiac sarcoidosis (CS) treated with ICD. Observational studies of patients with definite or probable CS and ICD implantation were identified from multiple databases from inception to 21 st May 2021. Outcomes of interest included appropriate and inappropriate ICD therapies in addition to all-cause mortality. Study quality was assessed individually using the Newcastle Ottawa Scale (NOS). Eight studies were identified comprising 530 patients, with follow-up period of 24 to 66 months (weighted average 40 months). Mean age was 53.9 years with ejection fraction of 41.3%. Overall incidence of appropriate therapy, reported in all studies, was 39% during follow-up. Left ventricular systolic dysfunction (LVSD) with ejection fraction < 40% was a predictor of appropriate therapy in the majority of studies, as were sustained VAs during electrophysiological testing (EP) in one study. Inappropriate therapy was documented in six studies and primarily driven by atrial arrhythmias. All-cause mortality was reported in six studies, with incidence of 6.0% over a median follow-up period of 42 months. Only three studies achieved good quality in the comparability domain of NOS. Conclusions: Appropriate ICD therapy in patients with CS is commonly associated with LVSD, which may act as a surrogate for scar burden. The utility of EP testing in this setting remains unclear.