Recurrent Acute Myocarditis : Characteristics, Etiology, Prognosis and Genetic Basis.

Acute myocarditis (AM) is an inflammatory disease of the myocardium caused by different infectious and non-infectious triggers. It is a major cause of sudden cardiac death, with also long-term adverse outcomes in survivors. The incidence and predictive factors of recurrent AM (RAM) are unknown.

Arrhythmogenic cardiomyopathy (ACM) is a genetically-determined or acquired arrhythmogenic disorder of the myocardium. With an incidence of 1/5000, genetic ACM is the consequence of pathogenic variants in genes encoding for desmosomal and cytoskeleton proteins. Originally described as a right ventricular disease (ARVC), genetic ACM is increasingly recognized as a left (ALVC) or biventricular entity. Genetic ACM may manifest with various clinical presentations, with a predisposition to acute and chronic heart failure, ventricular arrhythmias and sudden cardiac death. Pathophysiology of genetic ACM at early stages remain widely elusive.

Myocardial inflammation has been consistently reported in patients with genetic ACM, but the exact nature of their association is a matter of debate. The temporal association between RAM episodes and the later diagnosis of genetic ACM is speculative, and it has been hypothesized recently that RAM episodes might reflect early active phases in the development of a genetic ACM.

The investigators aim to study the temporal association between RAM episodes and the later diagnosis of an ACM.

Consecutive patients with at least two episodes of AM and referred to a tertiary university referral center (pop. 1.500.000 inhabitants) for clinical expertise, follow-up and etiological work-out were prospectively included in this registry.