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Corvisart introduced the term ‘myocarditis’ in 1812,1 but it would take up to 1987 before the Dallas classification was accepted for standardising the diagnostic criteria.2 The gold standard for diagnosis now is endomyocardial biopsy (EMB), combining the Dallas criteria with immunohistochemistry for inflammation and PCR for the detection of viruses (reviewed in Dennert et al),3 according to the 1995 WHO classification of cardiomyopathies.4 Of all patients with myocarditis 20% or more will develop dilated cardiomyopathy (DCM),5 which is induced by chronic inflammation or viral persistence after initial acute myocarditis (AMC).6 A high prevalence of parvovirus B19 (PVB19), human herpes virus 6 or the combination of the two viruses exists in patients with ‘idiopathic’ DCM, suggesting that the persistence of these viruses may relate to a worse prognosis.3 5 6 The type of clinical presentation plays an important role in the prognosis; heart failure-like symptoms would have a higher mortality than infarct-like symptoms.5 Patients with recovered left ventricular ejection fraction are always thought to maintain their normalised cardiac function. They are discharged from follow-up or medical treatment, and data on the progression of cardiac function and long-term prognosis of these patients are lacking. The present study challenges this approach.
The study by Escher et al,7 published in this issue of Heart (see page 709), prospectively studied 50 patients with AMC, which all underwent EMB irrespective of their cardiac function. They examined their …