Corticoid Therapy in Acute Myocarditis

Inclusion Criteria: * Age ≥ 18 years * Written signed informed consent * Affiliation to the French health care system or to another social protection scheme with the exception of State Medical Aid * Active myocarditis defined by (all items are required): * Acute chest pain and/or unexplained heart failure and/or syncope and/or sustained ventricular arrhythmias and/or aborted sudden death and/or cardiogenic shock and/or ECG modification (atrioventricular block or bundle branch block or sinus arrest or ST or T waves change or ventricular arrhythmia or atrial fibrillation or abnormal Q waves) * And troponin rise (1,5 times the normal range) * And diagnosis of active myocarditis on Cardiac Magnetic Resonance (according to Lake-Louise criteria) or by histological evidence on endomyocardial biopsy (Dallas's criteria) * Left-ventricular dysfunction defined as LVEF \< 50% and/or GLS \< -16% assessed with 2D-TTE * Normal coronary angiography or CT Scan (without stenosis \> 50%) during the previous year Exclusion Criteria: * Active coronary disease * Other causes of chronic heart failure (coronary artery disease, primary valvular heart disease, congenital heart disease) * Other etiology of myocarditis requiring corticosteroids treatment as giant cells myocarditis, eosinophilic myocarditis and cardiac sarcoidosis or immune checkpoint inhibitor myocarditis * Other auto-immune or inflammatory disease requiring corticosteroids treatment within 6 months before enrolment * Pregnanc…