Late evolution of arrhythmogenic cardiomyopathy in patients with initial presentation as idiopathic ventricular fibrillation

Abstract

Diagnosis of arrhythmogenic cardiomyopathy in a later stage in patients initially presented with idiopathic ventricular fibrillation may be due to improvement of diagnostic tools, progression of disease, or misinterpretation of initially available data. Introduction Arrhythmogenic cardiomyopathy (ACM), also known as arrhythmogenic right ventricular dysplasia/cardiomyopathy, is an inheritable heart muscle disorder in which sudden cardiac death due to ventricular fibrillation (VF) may occur unexpectedly as the first manifestation of the disease. This event is usually preceded by a long preclinical phase. Thus, prior to this event, the disease may frequently go unnoticed owing to the absence of relevant symptoms. This early presymptomatic stage has been defined as “concealed stage,” which does not necessarily mean absence of disease; in the absence of symptoms, criteria for ACM diagnosis may even be already present. Since 2010, ACM diagnosis is made according to revised Task Force Criteria (2010 TFC) obtained by international consensus. Fulfillment of these 2010 TFC (ie, presence of 2 major, 1 major plus 2 minor, or 4 minor criteria) is required for “definite” ACM diagnosis. Although fulfillment of TFC is required for definite ACM diagnosis, in the early disease stage it is conceivable that VF may occur in the presence of most but not all criteria. These cases are often regarded as idiopathic VF (IVF). In contrast to VF due to ACM, in IVF all known cardiac, respiratory, metabolic, and toxicologic etiologies should have been excluded by the clinical evaluation available at the time of the arrhythmic event. However, in our experience, some survivors of initially unexplained cardiac arrest may develop “definite” ACM years after the index event, either by progression of the disease or by improvement of diagnostic tools.