The presence of cardiotropic viral genomes is not increased in atrial tissue of atrial fibrillation patients

Background: Infections with potentially cardiotropic viruses are associated with the development of atrial fibrillation (AF). However, whether direct viral infection of the atria is involved in the pathogenesis of AF is unclear. We have therefore analysed the presence of cardiotropic viral genomes in AF patients. Methods: Samples of left atrial tissue were obtained from 50 AF patients (paroxysmal, n = 20; long-standing persistent/permanent, n = 30) during cardiac surgery and from autopsied control patients (n = 14). Herein, the presence of PVB19, EBV, CMV, HHV‑6, adenovirus and enterovirus genomes was determined by polymerase chain reaction. The densities of CD45+ and CD3+ cells and fibrosis in the atria were quantified by (immuno)histochemistry. Results: Of the tested viruses only the PVB19 genome was detected in the atria of 10% of patients, paroxysmal AF (2 of 20) and long-standing persistent/permanent AF (3 of 30). Conversely, in 50% of controls (7 of 14) PVB19 genome was found. No significant association was found between PVB19 and CD45+ and CD3+ cells, or between the presence of PVB19 and fibrosis, in either control or AF patients. Conclusion: The presence of viral genomes is not increased in the atria of AF patients. These results do not support an important role for viral infection of the atria in the pathogenesis of AF.