Abstract 1615: Low Frequency Of Detection Of Viral Genomes In Endomyocardial Biopsies From Patients With Dilated Cardiomyopathy
Over the last several years, a number of studies have suggested the possibility that dilated cardiomyopathy (DCM) might ensue as the sequelae of myocarditis of viral etiology, with particular reference to the possibility that the persistance of viral genomes might support disease development and evolution. Very few studies, however, have addressed the issue of quantifying viral load in the heart of DCM patients, often leading to conflicting conclusions. This research was aimed at detecting and quantifying the levels of different DNA (adenovirus, EBV, parvovirus B19, HSV-1 and -2) and RNA (all enteroviruses) viruses in endomyocardial biopsies of adult patients with DCM and myocarditis.
METHODS and RESULTS: Real-time PCR-based methods were developed for the quantitative detection of the above listed viral genomes. The threshold for detection was in all cases at least 1 copy of viral genome/1000 cell equivalents. Analysis was performed in endomyocardial samples from patients with idiopathic DCM (n=32), familial DCM (2), peripartum DCM (1), tachycardia-induced DCM (1), post-myocarditis DCM (3), ARVD (3), RCM (1), active myocarditis (15). Control patients included 20 endomyocardial samples from surgical patients. None of the analysed samples (total: 58 patients, 20 controls) tested positive for enterovirus, EBV, HSV-1 and -2. One patient in the idiopathic DCM group tested positive for adenovirus (4.76 viral genome copies/1000 cell equivalents). Of interest, 31 patients tested positive for Parvovirus B19 (23/58, 39.6% in the pathology group; 8/20, 40% in the control group; viral load: 4.59–107.8 genome copies/1000 cell equivalents).
CONCLUSIONS: These results disfavour the hypothesis that the persistent infection of the myocardium by the analyzed viruses might represent a major cause of disease development in adult patients with DCM and myocarditis. One caveat of this conclusion is that only one sample was available per patient; however, the breadth of the negative result renders the possibility that a focal disease might have escaped detection unlikely. In contrast to the other viruses, parvovirus B19 was frequently detected in endomyocardial biopsies from both disease and control patients, supporting the notion that this is a common virus.