Right ventricular aneurysms complicating encephalomyocarditis virus myocarditis in mice

Area of Science:

• Virology
• Cardiology
• Pathology

Background:

• Encephalomyocarditis virus (EMCV) is a known cause of myocarditis.
• The long-term sequelae of viral myocarditis, particularly on right ventricular structure, are not fully understood.

Purpose of the Study:

• To investigate the potential for encephalomyocarditis virus infection to induce chronic cardiac abnormalities.
• To determine if viral myocarditis can lead to the development of right ventricular aneurysms.

Main Methods:

• BALB/c, C3H/He, and DBA/2 mice were inoculated with the M variant of EMCV.
• Mice were monitored for up to 8 months post-infection.
• Cardiac tissues were examined for pathological changes, focusing on the right ventricle.

Main Results:

• Right ventricular aneurysms were observed in 1.1% of infected mice (7 out of 647).
• These aneurysms developed between 8 and 10 months after viral inoculation.
• Histological analysis revealed transmural destruction of myocardial fibers and fibrosis in the chronic stage.

Conclusions:

• Viral myocarditis, induced by EMCV, can infrequently result in right ventricular aneurysms.
• These findings suggest a possible pathogenetic role for viral infections in conditions such as right ventricular dysplasia and Uhl's anomaly.