Background: ‏Today, coronary artery disease is a leading cause of death and morbidity in the world and recognition of all aspects of this problem appears to be necessary and important. In recent years in addition to traditional coronary risk factors, other new risk factors are presented that can affect coronary arteries and accelerate atherosclerosis process. One of the most important of these, are infections, specially with Chlamydia pneumonia. We aimed to study this possibility that is whether correlation between infection with Chlamydia pneumonia and Acute Myocardial Infarction. (AMI).

Materials and Methods: This research is a descriptive case-control study which evaluates frequency of infection with Chlamydia pneumonia in the 100 patients with AMI and 105 patients without any history or evidence of CAD admitted in sections of CCU and surgery, in Dr. SHARIATI and SINA hospitals in 2001. For this purpose we took 5ml blood sample from all of the patients, and tested for specific anti Chlamydia pneumonia antibodies (IgG & IgM) by ELISA method.

Results: Our study showed that 38 percent of control group patients and 54 percent of patients with AMI had positive titer of anti Chlamydia pneumonia antibody and so they were infected with Chlamydia pneumonia {OR= 1.9 (95% CI: 1.34 to 2.46)} (P< 0/001).

Conclusion: This study demonstrates that, there is significant correlation between infection with Chlamydia pneumonia and occurrence of AMI so treatment of this infection could be of profit.