Dilated cardiomyopathy associated with Chlamydia trachomatis infection. A 26-year-old man was admitted to hospital with acute myocarditis complicated by congestive heart failure, and atrial and ventricular arrhythmias. Detailed investigations to determine the aetiological factors involved yielded negative results, except for serological evidence of infection with Chlamydia trachomatis. During the follow-up period, dilated cardiomyopathy developed. To the best of our knowledge a similar case has not been reported previously. 