Myocarditis epidemiology


 * Associate Editor-In-Chief: Varun Kumar, M.B.B.S.;

Overview
In developed countries, myocarditis is generally due to viral infections such as coxsackie B, enterovirus,adenovirus, parvovirus B19, hepatitis C, and herpes virus 6. In developing countries, myocarditis is generally due to HIV and rheumatic heart disease.

Incidence
In routine autopsies, 1-9% of all patients had evidence of myocardial inflammation. In young adults, up to 20% of all cases of sudden death are due to myocarditis.

Etiology in Developed Countries
Viral infections are the most common cause of myocarditis in developed countries. Common viral causes include coxsackie B and enterovirus. The frequency of dilated cardiomyopathy secondary to myocarditis 7.5-10% per 100,000 annually with enteroviruses, with the Coxsackie-B viruses being the most common cause. Recent studies show that adenovirus, parvovirus B19, hepatitis C, and herpes virus 6 were the common causes for myocarditis.

Myocarditis secondary to lyme disease should be suspected in people traveling to regions where it is endemic, particularly if there are associated conduction abnormalities of the heart.

Etiology in Developing Countries
In South America, Chagas' disease (caused by Trypanosoma cruzi) is the main cause of myocarditis. Other causes in developing countries include rheumatic fever and HIV infection.

Race
No difference in frequency of myocarditis has been observed between the various races.

Gender
Myocarditis is slightly more frequent among males than females. This may be due to protection conferred by the ovarian cycle.