The symptoms at first are often vague and mild. Heart failure may develop, and sometimes blood clots form in the heart. Many other conditions, such as disseminated lupus erythematosus, Lyme disease, and rheumatic fever, can also involve the heart. Various chemicals and some drugs, particularly those used in the treatment of cancer, can damage the heart muscle.
Treatment is directed at the cause, once it has been discovered.
The patient must have complete rest and may require oxygen. Corticosteroid drugs might be helpful in severe cases, but must be used with caution. In addition, the physician must treat complications such as arrythmias and congestive heart failure.