[The sick sinus syndrome and lipid peroxidation: its possible role in the pathogenesis of the disease].

As many as 196 persons were examined. Of these, 106 were with a normal sinus rhythm and 90 had sick-sinus syndrome (SSS). Measurements were made of the level of malonic dialdehyde and the total antioxidant blood activity, the lipoprotein spectrum. Electrophysiological studies of the heart, ECG monitoring and bicycle ergometry were carried out. Maximal impairment of lipid peroxidation (LP) in type IIA hyperlipoproteinemia (HLP) was identified according to Fredrickson both in patients with SSS and without it. In patients with SSS, the rise of the closeness of the relationship between LP and HLP was observed. In patients with CHD and (or) EH, LP was mostly disturbed in EH and in associated CHD and EH (both in patients with and without SSS). As compared with the respective control groups, SSS patients showed considerable disorders of LP. It is suggested that LP disorders related to HLP may play a role in the pathogenesis of SSS.