[Access of torsades de pointes in Legionnaires' disease: an uncommon adverse effect of erythromycin].

We report the case of a 77-year-old man with legionnaires's disease who, immediately after an intravenous infusion of one gram of erythromycin presented with wave burst arrhythmia with widening of the QT space. The blood level of erythromycin at the time of this adverse reaction was the same as the peak observed in young subjects after intravenous administration of this drug. Fourteen similar cases were found in the literature. In vitro and in vivo studies have shown that erythromycin may exert on the cardiac muscle fibres an electrophysiological effect similar to that of class I antiarrhythmic agents.