Myocarditis is an uncommon disorder caused by viral infections such as coxsackie virus, adenovirus, and echovirus. It may also occur during or after various viral, bacterial, or parasitic infections (such as polio, influenza, or rubella).

The condition may be caused by exposure to chemicals or allergic reactions to certain medications and it can be associated with autoimmune diseases.

The heart muscle becomes inflamed and weakened, causing symptoms of heart failure, which may mimic a heart attack.

• History of preceding viral illness
• Fever
• Chest pain that may resemble a heart attack
• Joint pain/swelling
• Abnormal heart beats
• Fatigue
• Shortness of breath
• Leg edema
• Inability to lie flat

Total absence of symptoms is common

Additional symptoms that may be associated with this disease:

• Syncope (fainting), often related to arrhythmias
• Decreased urine output
• Other symtoms consistent with a viral infection - headache, muscle aches, diarrhea, sore throat, rashes

• Electrocardiogram (ECG)
• Chest X-ray
• Ultrasound of the heart (echocardiogram) -- may show weak heart muscle, an enlarged heart, or fluid surrounding the heart.
• White blood cell count
• Red blood cell count
• Blood cultures for infection
• Blood tests for antibodies against the heart muscle and the body itself
• Heart muscle biopsy - rarely performed

Treatment includes evaluation and treatment of underlying cause. This may require use of antibiotics, reduced level of activity, and low-salt diet. Steroids and other medications may be used to reduce inflammation. Diuretics (medicine to promote removal of body water via the urine) are also given.

If the heart muscle is very weak, standard medicines to treat heart failure are also used. Abnormal heart rhythm may require the use of additional medications, a pacemaker or even a defibrillator. If a blood clot is present in the heart chamber, blood thinning medicine is given as well.

• Heart failure
• Pericarditis
• Cardiomyopathy