Symptoms and clinical findings due to myocarditis can mimic a heart attack.
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Myocarditis is an inflammatory disorder of the heart, usually caused by a viral infection. Authors of a May 2001 review article in the journal "Heart" reported that at least 20 percent of people diagnosed with myocarditis go on to develop heart failure, a condition characterized by the heart's inability to adequately pump blood to the body. More specifically, myocarditis is associated with dilated cardiomyopathy, a cause of heart failure that may ultimately require a heart transplant.
Myocarditis is caused by inflammatory changes that can occur in the heart after an infection. Viral infections caused by adenovirus, influenza A, Epstein-Barr virus, hepatitis C and human immunodeficiency virus have been linked to myocarditis. Fungal and bacterial infections can also lead to the condition. It is not clear why some people develop myocarditis while others do not. Researchers speculate that many people with myocarditis experience subtle symptoms and do not seek medical attention. In other cases, myocarditis leads to intense chest pain that mimics a heart attack. Heart failure symptoms, including profound shortness of breath and palpitations due to abnormal heart rhythms, are also possible.
Dilated cardiomyopathy describes an enlarged, weakened heart. This condition is a recognized complication of myocarditis. In some cases, people with myocarditis develop a constellation of dramatic heart failure symptoms -- known as cardiogenic shock -- within days of a viral infection. Cardiogenic shock causes rapid fluid accumulation in the lungs and dangerously low blood pressure. In this situation, immediate life support and even a heart transplant may be necessary. In other cases, however, myocarditis slowly leads to chronic heart failure symptoms over weeks or months.
When people experience heart failure symptoms due to myocarditis, the underlying diagnosis of myocarditis is often not clear. In these cases, a heart biopsy may be performed, particularly if heart failure symptoms rapidly progress to cardiogenic shock. During a biopsy, small pieces of heart tissue are removed so that doctors can look for cellular and inflammatory changes in the heart under a microscope. Magnetic resonance imaging of the heart may also be performed. An MRI can show characteristic findings of myocarditis, such as patchy areas of inflammation that would not be seen due to a heart attack or other conditions.
Authors of a February 2006 article in the journal "Circulation" point out that no specific therapies exist for the treatment of heart failure due to myocarditis. Therapies such as mechanical ventilation to support breathing and medications to boost blood pressure can help stabilize people with myocarditis-related heart failure until acute inflammation subsides. If deterioration persists, a heart transplant might be considered. Chronic heart failure symptoms due to myocarditis are treated with standard heart failure medications, such as diuretics, beta blockers and angiotensin-converting enzyme inhibitors.