The objectives of this project are: 1) to comprehensively characterize a large national cohort of patients with suspected myocarditis, their clinical phenotype, care management, blood and imaging biomarkers, epidemiological, environmental and genetic data; 2) to retrospectively validate the accuracy of the new hsa-RNA-Chr8:96 biomarker for the diagnosis of myocarditis compared to conventional diagnosis; 3) to identify acquired and inherited mutations, and their interaction with the environment, which explain the susceptibility to myocarditis, its severity and response to treatment; 4) to study the lower incidence in women and the influence of age, considering socio-health and genetic factors.

The primary endpoint of the study will be the characterization of a broad national cohort of patients with suspected myocarditis or inflammatory cardiomyopathy. The secondary endpoints of the study will be (A) individual susceptibility to developing myocarditis or inflammatory cardiomyopathy, 1) identifying acquired and inherited genetic variants, and 2) from the persistence of gender, age, and socioenvironmental conditions; and (B) studying the correlation between the final diagnosis of myocarditis and the hsa-miR-Chr8:96 marker.

Inclusion Criteria:

• Presence of at least one compatible symptom and at least one objective finding in diagnostic tests (Figure 2), according to the consensus document of the European Society of Cardiology (1):

A. Clinical presentation:

• Acute chest pain: pericardial or pseudo-ischemic.
• Dyspnea on exertion or at rest for up to 3 months.
• Dyspnea on exertion or at rest for 3 months - 1 year.
• Unexplained palpitations / arrhythmias, sudden death recovered.
• Unexplained cardiogenic shock.

B. Findings in complementary tests:

• ECG: new onset AV block, new onset bundle branch block, ST segment elevation/depression, T wave inversion
• Elevation of TnI/TnT
• Segmental or global contractility alterations not explained by other causes
• Positive Lake Louise criteria in cardiac MRI (13) (Annex III Figure S1) • Patients who have given their informed consent.

All patients with clinical suspicion of myocarditis or inflammatory cardiomyopathy will be included, based on the presence of compatible clinical findings.