EARLY-MYO-Myocarditis Registry

\[Inclusion Criteria\]:

1. Definitive diagnosis of myocarditis - A definitive diagnosis of myocarditis is based upon identification of diagnostic findings on EMB, including histology (Dallas criteria) as well as immunohistochemical stains.
2. Criteria for clinically suspected myocarditis - We adopted the 2013 European Society of Cardiology (ESC) position statement criteria for "clinically suspected" myocarditis, which require that a patient have at least one of the following clinical presentations of myocarditis and at least one diagnostic criteria; if the patient is asymptomatic at least two diagnostic criteria are required. A diagnosis of clinically suspected myocarditis also generally requires the absence of other clinical conditions that could explain the clinical findings such as cardiovascular disease (eg, angiographically significant CAD \[coronary stenosis ≥50%\], valve disease, or congenital heart disease), or an extra-cardiac condition (eg, hyperthyroidism). While it is possible to make a diagnosis of "clinically suspected" myocarditis in a patient with a concomitant condition such as CAD, clinical findings must be carefully reviewed to determine whether findings can be explained by a single disease process or whether the patient likely has at least two separate conditions. Clinical suspicion is higher with greater numbers of fulfilled criteria unrelated to other conditions .

   * Clinical presentations:

     * Acute chest pain (pericarditis or pseudo-ischemic)
     * New-onset (days up to three months) or worsening of dyspnea at rest or exercise, and/or fatigue, with or without left and/or right HF signs
     * Palpitation, and/or unexplained arrhythmia symptoms and/or syncope, and/or aborted sudden cardiac death
     * Unexplained cardiogenic shock
   * Diagnostic criteria:

     * ECG/Holter stress test features - New 12-lead ECG and/or Holter and/or stress testing abnormalities with any of the following: first to third degree atrioventricular (AV) block or bundle branch block, ST/T wave change (ST elevation or T wave inversion), sinus arrest, ventricular tachycardia or fibrillation, asystole, atrial fibrillation, significantly reduced R wave height, intraventricular conduction delay (widened QRS complex), abnormal Q waves, low voltage, frequent premature beats, or supraventricular tachycardia.
     * Elevated troponin T or troponin I.
     * Functional and structural abnormalities on cardiac imaging (echocardiogram, angiogram, or CMR) - New, otherwise unexplained abnormality of LV and/or RV function (regional wall motion abnormality or global systolic or diastolic dysfunction); such abnormality may occur with or without one or more of the following: ventricular dilatation, increased ventricular wall thickness, pericardial effusion or intracavitary thrombus.
     * Tissue characterization by CMR - Late gadolinium enhancement (LGE) and/or findings consistent with edema in pattern suggestive of myocarditis. (See 'Cardiovascular magnetic resonance' below.)
   * The following ancillary features support the clinical suspicion of myocarditis:

     * Fever ≥38.0 degrees C at presentation or during the preceding 30 days with our without associated symptoms (eg, chills, headache, myalgias, malaise, decreased appetite, nausea, vomiting, or diarrhea).
     * Prior clinical suspected or definite myocarditis.
     * Exposure to toxic agents.
     * Extra-cardiac autoimmune disease.

\[Exclusion Criteria\]:

1. Patient who is unable to comply with the follow-up schedule.
2. Patient who has any medical conditions that in the opinion of the investigators will not be appropriate to participate in the study.
3. Patient has a life expectancy of less than 6 months due to any condition.