In “Chlamydia Pneumoniae Infection and Disease”, Friedman H (Ed), et al. 2004, the authors reported studies which identified chlamydia pneumonia, by PCR testing and direct examination of heart tissue, in patients with myocarditis, endocarditis, and dilated cardiomyopathy. In the patients for whom treatment was stated, those given a macrolide or doxycycline showed improvement or resolution of their disease; and those given penicillin developed chronic fatigue or died.