Although many cases of lymphocytic choriomeningitis have been reported since 1933, when the etiology of the disease was established,1 no reports of cardiac involvement in this disease have been found. It is the purpose of this paper to present 2 cases in which clear evidence of cardiac involvement has been observed.
Lymphocytic choriomeningitis is an acute febrile illness with symptoms referable to the central nervous system. It accounts for 3% to 5% of all cases of aseptic meningitis.2
The reservoir of infection is the field mouse, and surveys have demonstrated that up to 20% of field mice may be so infected. The mode of transmission is usually from dried mouse urine, and the portal of entry is by the inhalation or ingestion of this common barnyard contaminant. The disease usually occurs in the fall and winter, presumably because it is at that time that the field mouse enters