Diagnosis and management of arrhythmogenic cardiomyopathy: a case report

Arrhythmogenic cardiomyopathy (ACM) is a genetically determined myocardial atrophy which progressively extends from the epicardium towards the endocardium, resulting in wall thinning. It is one of the leading causes of sudden death in young people. Postmortem studies demonstrate that up to 70-80% of the cases have biventricular involvement. Variable penetrance and expressivity results in a wide phenotypic spectrum, challenging diagnostic accuracy of advanced multimodality imaging tools. Prompt recognition, non-invasive imaging, risk stratification for sudden cardiac death (SCD), and preventive measures are paramount to improve prognosis.

Here, we present a 22-year-old Black male who was referred to our electrophysiology clinic with palpitations, remote syncope, and a family history of SCD. Over 3 years, he developed gradually worsening symptomatic palpitations. While physical exam and transthoracic echocardiography were unremarkable, his cardiac magnetic resonance imaging was consistent with biventricular ACM. Genetic testing confirmed ACM, revealing double heterozygosity in DSG2 and PKP2. Given the elevated estimated risk of life-threatening dysrhythmias, a subcutaneous cardiac defibrillator was successfully implanted.

Frequently, patients with ACM have more than one mutation in the same gene (compound heterozygosity) or in a second gene (double heterozygosity). Genetic counselling is strongly recommended for family members of the proband. The diagnosis of ACM may be mimicked by other diseases (cardiac sarcoidosis, dilated cardiomyopathy, amyloidosis), thus genetic testing can be useful to determine the presence of the disease. The present report provides an overview of the clinical course, diagnostic criteria, risk stratification, and prognostication for patients with ACM.