[Heart pathology of the extracardiac origin. X. Heart diseases of viral etiology].

Inflammatory processes affecting the heart frequently involve both the myocardium (myocarditis) and the pericardium (pericarditis). The syndromes of myocarditis and pericarditis are sufficiently distinct in clinical presentation and pathophysiology to warrant separate consideration. Viruses are the most important infectious cause of myocarditis in Western Europe. Enteroviruses and especially group B Coxsackie have been the major agents implicated. Patients may be asymptomatic or may have a rapidly progressive fatal disease. The gold standard for the diagnosis is endomyocardial biopsy. The application of "in situ" hybridization techniques and methods that detect or amplify viral nucleic acids may prove useful. Treatment of myocarditis should be directed at the specific etiology agent involved whenever possible. Because of the difficulties encountered in establishing a specific etiologic diagnosis, most cases of acute self-limited pericarditis are classified as idiopathic. Many of these are likely to be caused by viruses. As with myocarditis, most diagnose have been based upon the isolation of the virus from other body sites and/or demonstration of at least a fourfold rise in antibody titer after the acute illness. Among the challenges for the future will be the application of new techniques to expand our understanding at the molecular level of how viruses interact with target cell to alter function. Improved understanding of these aspects should lead to new approaches to the diagnosis, prevention and therapy of viral diseases.