The term myocarditis refers to inflammation of the heart muscle. It is most often due to viral illness. Other causes include drug abuse and autoimmune disorders such as systemic lupus erythematosus. Viral myocarditis is relatively common, but most cases are very mild and never come to the attention of the doctor. However, some cases are severe and can lead to considerable impairment in the capacity of the heart to pump efficiently, resulting in severe heart failure. It is the result of poor contraction or electrical instability of the heart due to the inflammation of the heart muscle.
What are the symptoms?
Most patients feel feverish and have generalised aches and pains as with any other viral illness. When the heart is severely affected the patients feel tired and breathless. Chest pain and palpitations are relatively common under these circumstances.Apart from a rapid heart rate, the doctor may not find any other abnormalities when examining the patients with mild myocarditis. However, in severely affected individuals there is evidence of heart failure.
How is it diagnosed?
Simple blood tests may demonstrate markers of inflammation. The ECG may show changes, which are usually non-specific and occur in many other cardiac diseases. However, the patient’s symptoms and the presence of a fever may raise the suspicion of myocarditis. An echocardiogram (ultrasound of the heart) will reveal an enlarged heart, which is poorly contracting. In very mild cases both the ECG and the echocardiogram may be normal and in these situations one should exercise caution and not participate in any sporting activity when symptoms of a flu-like illness are present. In patients presenting with prominent cardiac symptoms and signs, the diagnosis can be confirmed by a biopsy (small specimen of the heart) taken from the right ventricle. More recently, MRI has emerged as a useful method of diagnosing an inflamed myocardium (the heart’s muscular wall).
Treatment and advice
All patients should rest. Patients with heart failure and complicated electrical disturbances of the heart require hospital admission to manage these complications. Steroids are reserved for patients with auto-immune myocarditis at cardiac biopsy.
Refrain from sporting activity until all symptoms have subsided and the ECG and echocardiogram appearances are normal. Generally competitive athletes are advised to refrain from sporting activities during flu-like illness until the symptoms settle, as the majority of cases of myocarditis produce no cardiovascular symptoms.
Over 75% of the patients improve within two weeks without any complications. Approximately 10% of patients proceed to develop dilated cardiomyopathy and require life long treatment with heart failure medication.