Myocarditis is inflammation of the cardiac muscle usually following an infection, trauma or ischaemic event to the heart. It is also associated with rheumatological diseases such as SLE. Myocarditis can be acute or chronic. For most cases in routine clinical practice, a specific aetiology is not found. Viruses remain the most common cause, and often are presumed to be the causative agent in cases without a proven aetiology. The viruses identified include adenovirus, echovirus, CMV, influenzae or coxsackievirus.