A group from Paris, France has reported a case of fulminant HHV-6 myocarditis in a 28-year-old immunocompetent patient. As the authors note in their report, “HHV-6 is one of the most frequent viral causes of myocarditis, found in up to 23% to 36% of cases in series with endomyocardial biopsies, [and] is associated frequently with acute and chronic heart failure…as opposed to other viral causes of myocarditis, HHV-6 infection, although rarely symptomatic in the early stage, is likely to have a worse prognosis.” HHV-6 myocarditis can be challenging to definitively diagnose in the clinical setting. However, the group suggests that, together with newly available multiplex PCR microarray assays, cardiac magnetic resonance (CMR) may be an important tool for the timely diagnosis and clinical management of this condition.
In this case, the authors compared their CMR findings—uniquely combining assessment of cardiac anatomy and dynamics with noninvasive tissue characterization—with recent reports of HHV-6 myocarditis that suggested characteristically marked septal thickening, as evidenced by echocardiography, and complete AV block for differential diagnosis. In addition, the group implemented multiplex PCR-microarray assay techniques that revealed only the presence of HHV-6 in the myocardium and splenic tissues of the patient. Taken together, the authors indicate that “these recent developments in both imaging and virology may suggest that early image-guided endomyocardial biopsy and perhaps early LV assistance should be considered in severe forms of myocarditis confirmed by CMR, such as in the present case.”
As the prognosis of HHV-6 myocarditis is particularly poor, the authors hope this report will raise awareness of the usefulness of CMR to diagnose this and other unusual forms of viral myocarditis, as well as the effective utilization of endomyocardial biopsies to characterize histological lesions and identify the viral cause of inflammation in a timely fashion. The authors suggest that such a multidisciplinary diagnostic approach might constitute the first step to improve the clinical management and treatment of severe infectious myocarditis.