Perspective:

The following are 10 points to remember about this position statement on myocarditis:

1. Myocarditis presents in many different ways, ranging from mild symptoms of chest pain and palpitations associated with transient electrocardiographic (ECG) changes to life-threatening cardiogenic shock and ventricular arrhythmia.

2. Noninvasive imaging techniques such as cardiac magnetic resonance (CMR) imaging can be useful in making the diagnosis of myocarditis and for monitoring disease progression, but the position statement strongly endorses the concept that endomyocardial biopsy (EMB) should be the gold standard for the diagnosis of definite myocarditis.

3. A standard 12-lead ECG should be performed in all patients with clinically suspected myocarditis. All patients with clinically suspected myocarditis should also undergo a standard transthoracic echocardiogram at presentation.

4. CMR findings consistent with myocarditis should be based on Lake-Louise criteria. CMR does not replace EMB in the diagnosis of myocarditis and should not delay EMB in life-threatening presentations.

5. Troponins, erythrocyte sedimentation rate, and C-reactive protein levels should be assessed in all patients, but routine viral serology testing is not recommended. All patients with clinically suspected myocarditis should be considered for selective coronary angiography and EMB.

6. Tissue obtained from EMB should be analyzed using histology, immunohistochemistry, and viral polymerase chain reaction (PCR) (on heart tissue and a blood sample). At least three myocardial samples, each 1-2 mm in size, should be taken (from the right or left ventricle) and immediately fixed in 10% buffered formalin at room temperature for light microscopy; additional samples should be taken, snap frozen in liquid nitrogen, and stored at −80°C, or stored in RNA later tubes at room temperature, for viral PCR.

7. Patients with a life-threatening presentation should be sent to specialized units with capability for hemodynamic monitoring, cardiac catheterization, and expertise in EMB. Cardiac transplantation should be deferred in the acute phase because recovery may occur, but can be considered for aerodynamically unstable myocarditis patients, including those with giant cell myocarditis, if optimal pharmacological support and mechanical assistance cannot stabilize the patient.

8. Physical activity should be restricted during the acute phase of myocarditis and for at least 6 months in athletes and nonathletes. This recommendation is based upon expert opinion of this task force.

9. Immunosuppression should be started only after ruling out active infection on EMB by PCR. Based on experience with noncardiac autoimmune disease, the task group recommends consideration of immunosuppression in proven autoimmune (e.g., infection-negative) forms of myocarditis, with no contraindications to immunosuppression, including giant cell myocarditis, cardiac sarcoidosis, and myocarditis associated with known extracardiac autoimmune disease.

10. All patients with myocarditis should be followed with clinical assessment, ECG, and echocardiography.