Background: Cardiac syndrome X (CSX) is a condition in which patients have the pain of angina despite normal coronary angiogram. Recently, Helicobacter pylori (H. pylori) bacteria has been associated with CSX. However, there is no obvious data about the frequency of its virulent strain (cytotoxine associated gene A: CagA) in patients with CSX. We surveyed the frequency of H. pylori and CagA antibodies in patients with cardiac syndrome X and healthy controls. Materials and Methods: Plasma samples from 100 CSX patients (61 females and 39 males; mean age: 51.8 ± 12.3 years) and 100 healthy controls (61 females and 39 males; mean age: 48.9 ± 6.3 years) were tested for the presence of IgG antibody to H. pylori using enzyme linked immunosorbent assay (ELISA) method. Also, infected patients were determined by the presence of IgG antibody to CagA by ELISA method. Statistical analysis was carried out using chi-square test and independent samples T-test. Results: Ninety two percent (92/100) of patients were anti-H. pylori positive (anti-H. pylori+), while only 56.0% (56/100) of control group were anti-H. pylori+ (P<0.01). However, prevalence of anti-CagA positive (anti- CagA+) in H. pylori infected- CSX patients and control groups were 59.8% (55/92) and 60.7% (34/56), respectively (P >0.05). Conclusion: Thus, due to the high frequency of anti-H. pylori in CSX patients, and the probable causative effect of chronic infection in vascular diseases, it is suggested that H. pylori has a probable role in the pathogenesis of CSX.
Key words:Cardiac syndrome X,CagA,chest pain,Helicobacter pylori.