The goal of this observational study is to observe if ultra-sensitive troponins (us) measurement between 3 and 6 months after the acute event will be sensitive enough to dispense with all other examinations, particularly cardiac magnetic resonance imaging (MRI), in patients suffering from myocarditis.

The investigators will collect patient events by telephone, once a year for 4 years.

Myocarditis is a frequent pathology with a heterogeneous initial clinical presentation. The long-term course of the disease is variable, with the possibility of healing and recovery, but also the likelihood of long-term deterioration, with the development of true dilated cardiomyopathy. While diagnostic criteria in the initial phase are well codified, notably with cardiac MRI, follow-up methods are less standardized. Re-evaluation between 3 and 6 months is not carried out by all teams, and if it is, the examinations performed vary from one team to another. Grenoble team has demonstrated the prognostic role of MRI reassessment at 3 and 6 months. It is also common to measure troponins to detect chronic myocarditis. However, this assay has evolved over time with the advent of ultra-sensitive troponins (us). These appear to be much more sensitive, and this increased sensitivity may lead to a change in care strategies.

For example, in the management of chest pain in emergency departments before the era of us troponins, the use of coronary CT scans improved patient management. This benefit of imaging has disappeared since the advent of troponin us.

The hypothesis of investigators is that troponin us measurement between 3 and 6 months after the acute event will be sensitive enough to dispense with all other examinations, particularly cardiac MRI, in order to identify patients at risk of poor prognosis.

Inclusion Criteria:

• Male or female patients over 18 years of age

• Patients hospitalized at Grenoble Alpes University Hospital and Lyon University Hospital between June 2016 and June 2025

• Having presented chest pain and ≥1 diagnostic criteria or if no chest pain, presence of ≥2 diagnostic criteria below :

  • Electrical abnormalities (supra- or sub-ST, T-wave inversion, atrioventricular blocks 1-3 conduction disorders)
  • Elevation of cardiac biomarkers (troponin)
  • Kinetic abnormalities on cardiac ultrasound

• Associated with ≥2 MRI criteria of tissue abnormality (edema, hyperhemia, myocardial fibrosis)

• Patient affiliated to a social security scheme or beneficiary of such a scheme

• No opposition to participation

Exclusion Criteria:

• Absence of documented coronary artery disease (cardiac CT or coronary angiography) or age <30 and low risk of coronary artery disease.
• Myocarditis secondary to immunotherapy.
• Presence of documented coronary artery disease (coronary angiography or cardiac CT)
• Presence of cardiomyopathy (hypertrophic cardiomyopathy, dilated cardiomyopathy)
• Infiltrative heart disease (sarcoidosis or cardiac amyloidosis)
• Severe valve disease
• Takotsubo
• Constrictive or chronic pericarditis
• Loeffler's endocarditis
• Non-compaction of the left ventricle
• Cardiac tumor
• Pulmonary embolism
• Coronary spasm
• Patients covered by articles L1121-5 to L1121-8 of the French Public Health Code (pregnant women, parturients, nursing mothers; persons deprived of liberty by judicial or administrative decision; protected adults)

Any patient hospitalized for myocarditis at Grenoble Alpes University Hospital (CHUGA) or at Lyon University Hospital, with standardized reassessment at 3-6 months.