Infection by CagA-positive Helicobacter pylori strains in patients with ischemic heart disease: prevalence and association with exercise-induced electrocardiographic abnormalities.

The role of H. pylori infection in increasing the risk of ischemic heart diseases (IHD) is still debated. We determined serologically the prevalence of overall H. pylori and CagA-positive H. pylori infection in 63 consecutive patients with IHD and 189 gender- and age-matched controls. We also determined in patients the influence of the infection and the CagA serological status on the results of an exercise ECG test and other parameters considered possible variables that may enhance the risk of IHD. The prevalence of H. pylori infection in patients and controls was 79.3% and 73.0%, respectively (P = 0.403) and that of CagA-positive H. pylori infection was 69.8% and 42.3%, respectively (P = 0.0002). The scores of the ECG S-T segment and T-wave abnormalities in the course of an exercise ECG in uninfected patients and in patients infected by CagA-negative and CagA-positive H. pylori strains were (mean +/- SD): 1.59 +/- 0.67, 1.92 +/- 0.64, and 2.19 +/- 0.70, respectively; (P = 0.011, 95% confidence limits of difference 0.15-1.07, CagA-positive infected vs uninfected patients). There was no intergroup difference in the levels of peripheral white blood cells, glucose, cholesterol, triglycerides, creatinine, and systolic and diastolic pressure. In conclusion, genetic heterogeneity of H. pylori could possibly explain some conflicting results concerning the association of H. pylori infection with IHD. Coronary vessels of IHD patients infected by CagA-positive H. pylori strains may be damaged more severely than those of uninfected patients.