Myocardial infarction associated with Chlamydia pneumoniae.

ABSTRACT

A 39-year-old black South African man with no recognised risk factors for coronary hart disease (CHD) except hypertension, died of a myocardial infarct (MI). The case was unusual because although hypertension is common, MI is rare in black South Africans. Serology indicated that the subject had previously had a Chlamydia pneumoniae infection. The primary lesion in the left anterior descending branch of the coronary artery was a ruptured atherosclerotic plaque in which C. pneumoniae was indentified by immunocytochemical, electron microscopic and polymerase chain reaction techniques. The organisms were detected in smooth-muscle cells, foam cells and interstitially, but not in adjacent unaffected tissue. C. pneumoniae DNA was also detected in the myocardium of the left ventricle in an area of the infarct. It is postulated that debris from the ruptured plaque was deposited in the muscle. The observations support the association between C. pneumoniae and CHD; for the first time the organism is identified in a lesion that ruptured and caused an MI.