Introduction
The potentially fatal arrhythmias secondary to cardiac sarcoidosis (CS) have spurred research into the use of the implantable cardioverter defibrillator (ICD) in this condition. Appropriate ICD therapy refers to either an appropriate shock, or correct device-based rhythm analysis and recognition of anti-tachycardia pacing, for ventricular tachyarrhythmias such as ventricular tachycardiac (VT) or ventricular fibrillation (VF). An Ellenbogen et al. article helped frame the utility of “appropriate therapy” as an important surrogate marker of sudden cardiac death (SCD) in non-ischaemic cardiomyopathies, albeit one that will over-estimate the benefits of ICD shocks(1). Inappropriate therapy, however, is a shock that is delivered in the absence of VT or VF, the consequence of which has been previously shown to lead to myocardial dysfunction, advancement of heart failure and increased mortality(2–4). Understanding the patient groups that receive appropriate therapies, as well as identifying those in whom device complications are more prevalent, will help guide future guidelines and recommendations to improve patient care.
Figure 1: Central illustration of appropriate & inappropriate therapies, as well as device complications in CS