Viral myocarditis--new aspects of pathomechanisms, diagnosis and therapy

The diagnosis of "viral myocarditis" remains uncertain in most cases, despite varied efforts to obtain diagnostic criteria and techniques. The combination of virological, histological and immunohistological data may offer an opportunity to improve diagnosis. The pathophysiological processes which are involved in the transition from myocarditis into dilated cardiomyopathy are still unclear. A variety of new data point out that viral infection induces a loss of self-tolerance and subsequent autoaggression towards myocardial structures. The management of viral myocarditis remains problematic and a specific form of therapy still does not exist. Studies on immune suppressive therapy are contradictory. Moreover, in these studies the diagnostic criteria were non-uniform and the number of patients was low. Nevertheless, immune suppressive therapy can be very effective in individual cases. But until now, a clear decision cannot be made on the selection of those patients who would respond favourably to immune suppressive therapy. Only controlled studies which consider the aetiology, the grade of clinical severity, the duration of clinical symptoms, the degree of cellular infiltration, and the histological alterations may answer the questions concerning the benefit of immune suppressive therapy for viral myocarditis and its sequelae. Until these studies are available, the general implementation of immune suppressive therapy in viral heart disease should not be recommended, especially in view of the incidence of side effects.