In order to assess the real significance of some plasma and vascular indices in disorders of the stable course of coronary heart disease (CHD) in chronic bacterial- and viral infection-invasion, we determined the blood plasma lipid hydrogen peroxide (LHP) activity, a direct index of the lipid peroxidation degree, and measured the concentration of specific antibodies to Chlamydia pneumoniae (C. pneunoniae), herpes simplex virus type 1 (HSV-1), cytomegalovirus (CMV) and Epstein-Barr virus (EBV) by means of the enzyme-linked immunosorbent assay (ELISA). We examined a total of 70 patients presenting with CHD combined with a concomitant infection both with a stable course of the disease (Group One) and acute coronary syndrome (Group Two), as well as 50 infected people without verified signs of coronary atherosclerosis (Group Three).

 The comparison group consisted of patients with CHD, being seronegative for the causative agents referred to above. The condition of the major vessels was appropriately assessed by means of duplex ultrasonography (DU).

 Resulting from the findings of the carried out investigation, we singled out a triad of symptoms characteristic of the transformation of the chronic infectious process into the recurrent phase, which for the CHD patients with the presence of the conventional risk factors of atherosclerosis might become a cause of the disordered stable course of the disease and development of acute ischaemic attacks.

 The revealed alterations seemed to have been based upon an infectious-origin inflammatory lesion of the vessels, which was duly confirmed by duplex ultrasonography.