Right ventricular aneurysms complicating encephalomyocarditis virus myocarditis in mice.

Inbred strains of BALB/c, C3H/He and DBA/2 mice were inoculated intraperitoneally with the M variant of encephalomyocarditis virus with a titer of 100 TCD50 per 0.1 ml and followed up to the 8th month. Right ventricular aneurysms were noticed in 7 hearts of these 647 mice (1.1%) sacrificed from 8 to 10 months after inoculation with the virus. Myocardial fibers of the right ventricle were destroyed transmurally and fibrosis was found in the chronic stage. This study demonstrated that viral myocarditis may cause right ventricular aneurysms, albeit infrequently, suggesting a pathogenetic role of viral infection in right ventricular dysplasia or Uhl's anomaly.