Estimation and prognostic value of the patients simpatovagal status in the acute period of myocardial infarct with ST segment elevation

The aim of the study was to analyze the impact of the status of cardiac autonomic nervous regulation on the fragmentation activity, development and progression of heart failure, and the long-term prognosis in patients with early ST segment elevation myocardial infarction.Material and Methods. The study included 143 subjects; 54 healthy volunteers were examined to identify normal values of heart rhythm variability parameters. The observation group comprised 89 patients with ST segment elevation myocardial infarction who underwent 24-hour ECG monitoring at day 7 to 9 as well as at 24 and 48 weeks with follow up assessment of heart rate variability and late ventricular potentials. At the time points, the levels of brain natriuretic peptide and highly sensitive C-reactive protein were determined. Patients underwent a 6-min walk test every 12 weeks. The development of repeated cardiovascular events has been monitored as an end-point. Patients were assigned to two groups according to results of heart rhythm variability analysis at day 7–9 after onset of ST segment elevation myocardial infarction: group 1 had normal heart rate variability; group 2 had increased sympathetic impact on rhythm.Results. In group 1, a pronounced regression of the brain natriuretic peptide level was registered 24 week after onset of ST segment elevation myocardial infarction. The value of C-reactive protein decreased in all groups. A favorable transformation of the indices reflecting the fragmentation activity — high-frequency low-amplitude and root mean square — of the myocardium was recorded only in the group with normal heart rate variability parameters. The risk of repeated cardiovascular events during 48 weeks after ST segment elevation myocardial infarction was significantly higher in the group with dominant sympathetic activity than in the group with normal status of the autonomic nervous system.Conclusion. Hypersympathicotonia in the acute period of ST segment elevation myocardial infarction was associated with an increased relative risk of repeated cardiac events and negatively affected the dynamics of laboratory parameters indicative of heart failure development and progression.