Arrhythmia or myocarditis: a novel clinical form of Legionella pneumophila infection in children without pneumonia.

The possibility that L. pneumophila causes cardiac disorders without respiratory or pulmonary symptoms in childhood was investigated. Out of 20 children with cardiac troubles of unknown aetiology, three showed a four-fold antibody increase or fall in titre against L. pneumophila antigens by the IFA test. Two children, aged 7 months and 2.5 years, had self-limiting arrhythmia and a third, 10-year-old, was suffering from a severe myocarditis. There was no serologic evidence of concurrent infection by respiratory or coxsackie B viruses nor by M. pneumoniae. It is suggested that Legionella infection should be considered in cardiac diseases in childhood, even if pneumonia is lacking.