Time	Events
Patient 1
Days 0	Onset of fever, asthenia, abdominal pain, and diarrhoea.
Day 5	Hospital admission. Finding of significant increase in acute phase proteins and myocardial injury. Ecocardiography revealed a global reduction in left ventricular ejection fraction (EF 36%) and mild ventricular dysfunction with tricuspid insufficiency. Diagnosis of multisystem inflammatory syndrome in children (MIS-C). Starting treatment with Methylprednisolone, IVIG, Enoxaparine, and Enalapril.
Day 8	Onset of bradycardia. 24-h Holter monitoring showed mean heart rate (HR) 51 with sinus rhythm.
Day 12	Starting treatment with Anakinra.
Day 14	Improvement of HR and systolic function.
Day 17	Cardiac magnetic resonance imaging (MRI) showed sub-acute phase myocarditis, with sub-epicardial involvement of left ventricle. EF 63%.
Day 28	24-h Holter monitoring confirmed the normalization of HR.
Patient 2
Day 0	Onset of asthenia, laterocervical lymphadenomegaly, fever, and diarrhoea.
Day 3	Hospital admission. Laboratory tests showed significant increase in acute phase proteins and myocardial injury markers. Diagnosis of MIS-C.
Day 4	Starting treatment with Methylprednisolone, IVIG, Enoxaparine, and Enalapril.
Day 6	Ecocardiography revealed thin flap of pericardial effusion (4 mm) with normal cardiac morphology and contractility (EF 62%).
Day 8	Onset of bradycardia. 24-h Holter monitoring showed mean HR 55 with sinus rhythm.
Day 13	Starting treatment with anakinra.
Day 15	Improvement of HR and systolic function.
Day 27	Cardiac MRI showed outcomes of myocarditis with sub-epicardial involvement of the mid-ventricular area. EF 59%.