Abstract
BACKGROUND: Myocardial disease is an important component of the wide field of cardiovascular disease. However, the phenomenon of multiple myocardial diseases in a single patient remains understudied. AIM: To investigate the prevalence and impact of myocarditis in patients with genetic cardiomyopathies and to evaluate the outcomes of myocarditis treatment in the context of cardiomyopathies. METHODS: A total of 342 patients with primary cardiomyopathies were enrolled. The study cohort included 125 patients with left ventricular non-compaction (LVNC), 100 with primary myocardial hypertrophy syndrome, 70 with arrhythmogenic right ventricular cardiomyopathy (ARVC), 60 with dilated cardiomyopathy (DCM), and 30 with restrictive cardiomyopathy (RCM). The diagnosis of myocarditis was based on data from myocardial morphological examination or a non-invasive diagnostic algorithm consisting of an analysis of clinical presentation, anti-cardiac antibody (Ab) titres, and cardiac MRI. RESULTS: The prevalence of myocarditis was 74.3% in ARVC, 56.7% in DCM, 54.4% in LVNC, 37.5% in RCM, and 30.9% in HCM. Myocarditis had a primary viral or secondary autoimmune nature and manifested with the onset or worsening of chronic heart failure (CHF) and arrhythmias. Treatment of myocarditis in cardiomyopathies has been shown to stabilise or improve patient condition and reduce the risk of adverse outcomes. CONCLUSIONS: In cardiomyopathies, the genetic basis and inflammation are components of a single continuum, which forms a complex phenotype. In genetic cardiomyopathies, myocarditis should be actively diagnosed and treated as it is an important therapeutic target.